LCT_Dau_tri_va_Luat.pdf

7/27/2019 LCT_Dau_tri_va_Luat.pdf

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AU TR VA LUAT_________________________________

TS. Le NetLut s, LCT Lawyers

Ging vin, Trngi hc Lut TP HCM

[email protected]

NXB I HC QUC GIA TP HCM 2005


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Muc luc

MUC LUC..................................................................................................................................................... 1

LI GII THIEU ........................................................................................................................................ 3

CHNG 1: QUYET NH TRONG NHNG CUOC AU TR THONG THNG ...................... 6

AU TR THONG THNG ...................................................................................................................... 6THAY OI KET QUA E THAY OI CHIEN LC CUA NGI CHI ............................................................. 8IEM CAN BANG NASH........................................................................................................................ 10QUY NH CUA PHAP LUAT VA KHAI NIEM TOI U HOA ......................................................................... 12

CUOC AU TR GIA HAI NGI CHI KHONG CO Y NH CONG TAC ..................................................... 13CUOC AU TR GIA HAI NGI CHI CO Y NH CONG TAC ................................................................. 15KET LUAN........................................................................................................................................... 17

CHNG 2: MOI TNG QUAN ONG VA CAC CAC CUOC AU TR M RONG ................19

AU TR M RONG VA PHNG PHAP "QUI NAP NGC" ....................................................................... 19PHNG PHAP "PHONG NGA" VA CAC CAM KET CHIEN LC .............................................................. 21AU TR TH CAP HOAN CHNH ........................................................................................................... 24KET LUAN........................................................................................................................................... 26

CHNG 3: TIET LO THONG TIN, YEU CAU CONG BO VA THAO LUAN LAI .......................27

T TNG CH AO HANH ONG.......................................................................................................... 27

KHAI NIEM VE GIAI PHAP CAN BANG HOAN CHNH BAYES .................................................................... 29THONG TIN C KIEM CHNG, T NGUYEN CUNG CAP THONG TIN VA MANH MOI ................................ 32LUAT YEU CAU CONG BO THONG TIN VA NHNG HAN CHE CUA LUAT ................................................... 33THONG TIN CO THE QUAN SAT C, QUI PHAM VA VAN E THAO LUAN LAI ........................................ 40S KHUYEN KHCH TOI U VA VAN E THAO LUAN LAI ........................................................................ 42HAN CHE KHA NANG THAO LUAN LAI .................................................................................................. 44KET LUAN........................................................................................................................................... 45

CHNG 4: PHAT TN HIEU, CHON LOC VA S DUNG CAC THONG TIN KHONG KIEMCHNG C ...........................................................................................................................................47

PHAT TN HIEU VA CHON LOC .............................................................................................................. 47MO HNH S DUNG THONG TIN KHONG KIEM CHNG C ................................................................... 48

PHAT TN HIEU VA VAI TRO CUA CAC QUY NH PHAP LUAT.................................................................. 55TIET LO THONG TIN VA CAC QUY NH VE VI PHAM HP ONG ............................................................. 57CHON LOC THONG TIN VA VAI TRO CUA CAC QUY NH PHAP LUAT ...................................................... 59KET LUAN........................................................................................................................................... 60

CHNG 5: UY TN VA CAC CUOC AU TR LAP LAI .................................................................62

PHNG PHAP QUY NAP VE TRC VA NHNG HAN CHE....................................................................... 62AU TR LAP LAI, CAU KET NGAM VA "QUI TAC CO" ............................................................................. 65


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UY TN, TRNG PHAT VA CONG TAC..................................................................................................... 68KET LUAN........................................................................................................................................... 70

CHNG 6: HANH VI TAP THE, CAC CUOC AU TR NGAM VA NHNG HAN CHE CUACAC MO HNH N GIAN .....................................................................................................................71

HANH VI TAP THE VA VAI TRO CUA PHAP LUAT .................................................................................... 72AU TR CHM ..................................................................................................................................... 73TM HIEU CAU TRUC CUA CAC CUOC AU TR M RONG ....................................................................... 77HANH VI TAP THE VA THONG TIN RIENG ............................................................................................... 81HANH VI TAP THE TRONG CAC QUYET NH TIEP THEO ......................................................................... 84HANH VI "THEO UOI"......................................................................................................................... 87KET LUAN........................................................................................................................................... 89

CHNG 7: THAO LUAN TRONG TRNG HP BAT CONG TAC ............................................90

MO HNH HOA VIEC PHAN CHIA LI TC T THNG MAI ..................................................................... 90QUY NH CUA PHAP LUAT TAO RA LOI THOAT ..................................................................................... 93MAC CA VA SAP XEP LAI DOANH NGHIEP ............................................................................................. 94

KET LUAN

........................................................................................................................................... 95CHNG 8: THAO LUAN VA THONG TIN .........................................................................................96

CAC MO HNH C BAN CUA TO TUNG ................................................................................................... 96MO HNH HOA CAC PHIEN TOA XET X VE BOI THNG THIET HAI ........................................................ 98THONG TIN VA THANH KIEN TRONG VIEC CHON LA ............................................................................ 99TRAO OI THONG TIN VA KIEM CHNG THONG TIN ............................................................................. 100KET LUAN......................................................................................................................................... 101

KET LUAN - THONG TIN VA CAC HAN CHE CUA LUAT ...........................................................102

NH NGHA ............................................................................................................................................106


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Li gii thieu_________________________________

Chung ta a tng lam quen vi au tr luan (hay con goi la ly thuyet tro chi - gametheory) qua bo phim c giai Oscar nam 2002 - Mot tam hon ep (A BeautifulMind). Tien e cua quyen sach nay la au tr luan co the cho chung ta cai nhn cu theve anh hng cua phap luat oi vi cach x s cua moi ngi. Phap luat muon cthc thi can phai "thuan long ngi", co ngha la no phan anh cach x s cua nhngngi co ly tr. Nh vay khong nhng chung ta phai hieu luat, ma luat phap cung canphai hieu cach x s cua chung ta. Khi bien soan quyen sach nay, cac tac gia at rahai muc tieu. Th nhat, ly thuyet ve au tr c s dung nh mot cong cu e tm hieucac nganh luat, t dan s, hnh s, thng mai en hanh chnh v.v. Th hai, ly thuyet

ve au tr c s dung e d oan nhng x s cua cac chu the khi phap luat thayoi, tren c s o co the kien ngh thay oi luat hay khong va nen ap dung luat nhthe nao e at c muc ch ma chung ta e ra.

au tr luan c von Neuman va Morgenstein xay dng t nhng nam 1930, tuynhien phai en khi John Nash cong bo cac cong trnh cua mnh (1953) th au tr mithc s c quan tam nh la mot cong cu kinh te hoc. Nam 1993, John Nash cungvi John Harsanyi va Reinhardt Selten nhan c giai Nobel kinh te ve nhng onggop trong mon au tr luan. Pham vi ng dung cua mon hoc nay rat ln: lam the naola chon c ngi mnh tin can, la chon oi tng e ket nap ang, la chon oi

tac e lam an, tm a iem kinh doanh, tm muc tieu quan s cua ke thu e tieu diet,phat hien nhng hanh vi li dung, tieu cc, tham o lang ph, hay am phan ky ket hpong vi oi tac. Trong kinh te, au tr la mot mon hoc phc tap va s dung rat nhieucac cong cu toan hoc hien ai. Tuy nhien quyen sach nay c bien soan cho luat gia,v vay cac cong thc toan hoc c lc bo. Chung toi ch yeu cau ngi oc nh cackhai niem c ban, suy ngh ve nhng van e phc tap mot cach logic va can than.

Quyen sach nay c bien soan da tren sn cua Game Theory and the Lawdo D.Baird, R. Gertner, va R. Picker bien soan nam 1994. Tuy nhien no lc bo bt cacphan khong quan trong va them nhng thay oi t nam 1994 en nay. ac biet, cacth du va gi y trong quyen sach a c thay oi va them cho phu hp vi hoan canhva nhu cau cua Viet nam, cho cac hoc vien muon tm hieu ve au tr, hay cac ngdung cua no khi ra trng cong tac. Nh en cau "biet mnh biet ngi, tram trantram thang" cua Ton T, chung toi tin rang quyen sach nay se rat co ch cho cac bankhi tm hieu cach suy ngh va cach x s cua moi ngi, va cach van dung phap luatsao cho co hieu qua nhat.


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Mac du au tr luan c e cap rat nhieu trong mon hoc luat va kinh te (law andeconomics) tai cac nc phat trien, Viet nam chung ta hien cha co mon hoc nay,tham ch au tr luan cung cha c giang day ai hoc kinh te. Trong tng lai khinhu cau hoi nhap nen kinh te, cung nh nhu cau gan giang day vi thc te cuoc songtr nen bc xuc, chung toi tin rang luat va kinh te, hay au tr luan se la nhng monau tien c nha trng la chon e giang day cho sinh vien.

Quyen sach c chia thanh 8 chng. Chng 1 gii thieu cach ap dung au tr luane tm hieu tai sao luat lai quy nh mot van e nh vay. Cong cu cua au tr luan lacac cuoc au tr hay cac tro chi (games), trong o chung ta phai tm hieu ve ngichi (player), chien lc hay cach chi cua tng ngi (strategy) va ket qua (payoff)trong tng nc i (move). Cac tro chi pho bien nhat la ngi tu (prisoner'sdilemma), san hu (hunt stag) va sap nga (matching pennies). Cac ket luan t

nhng tro chi nay c ap dung vao cac che nh phap luat nh hp ong hay boithng ngoai hp ong. Chng 2 xem xet cac chu the x s vi nhau nh the nao khimot so trng hp xay ra - th du cac cong ty oc quyen chen ep oi thu canh tranh,hay ben i vay khong tra c n cho ben vay. T o chung ta tm hieu ky hn hailoai au tr: au tr gia nhng ngi muon cong tac vi nhau (co-operative game) vaau tr gia nhng ngi muon canh tranh vi nhau (non co-operative game). loaisau chung ta co the lien he vi nhng bai hoc trong Binh phap Ton t.

Cac chng tiep theo se i vao nhng van e phc tap hn - khi chung ta gia thiet cacben cha biet thong tin ve nhau va khong biet phai x s vi nhau the nao. Trong cac

trng hp nh vay, phap luat can phai c quy nh sao cho cac ben t boc lo banchat cua mnh (revelation - th du - la ngi dung cam hay hen nhat, la ngi nhiettnh hay li dung, la ngi trung thc hay doi tra). Da tren cac thong tin nay machung ta co the ra quyet nh - th du khong giao v tr lanh ao cho nhng ngi hayli dung. Tuy nhien co the cho ho am nhiem vai tro thng thuyet, v ho de canhgiac ve oi tac hn nhng ngi qua vo t va nhiet tnh. Tng t, cac nha lam luatco the da vao cac thong tin nay ma ban hanh cac quy nh cho phu hp vi tnh hnhthc te. Th du khi mot ben b li dung, ho co quyen yeu cau vo hieu hp ong do bla doi hay e doa, hoac yeu cau am phan lai. o la noi dung cua Chng 3 (au trtrong hp ong), va Chng 4 (au tr va viec sap xep nhan s).

Chng 5 ban ve anh hng lau dai cua cac quy nh phap luat oi vi hanh vi cuacac chu the. Th du, luat hp ong hay luat kinh te phai quy nh the nao e cac chuthe yen tam kinh doanh hay cong tac lau dai vi nhau.

Chng 6 ban ve moi tng tac gia cac quy nh cua phap luat, cung nh anh hngcua mot hanh vi xau oi vi mot hanh vi khac. Cac trng hp nay c goi la hanh


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vi tap the hay phan ng day chuyen (domino effect, spillover effect hay collectiveaction). Pham vi ng dung cua chng nay chu yeu trong cac quy nh ve luat canhtranh hay luat s hu tr tue.

Chng 7 e cap en cau hoi - lam the nao e cac chu the kinh doanh co the amphan vi nhau tren tinh than bnh ang va cung co li, trong khi li ch cua ho oikhang nhau? e tra li cau hoi chung ta s dung ly thuyet ve au tr ve am phangia nhng ngi khong cung li ch (non co-operative bargaining), trong o van emau chot la tm thong tin ve oi tac. Pham vi ng dung cua chng nay la trong luatdoanh nghiep, au t nc ngoai, ngan hang, bao hiem hay pha san.

Chng 8 tiep tuc ban ve van e tng tac trong mot moi trng bien ong (dynamicbargaining), trong o cac quy nh cua phap luat phai d lieu rang mot ben co thongtin nhng khong muon cho ben kia biet. o cung la van e ve thong tin bat oi xng

(asymmetric information), de nay sinh ra viec li dung (moral hazard). Pham vi ngdung cua chng nay la luat hnh s (ve cac toi lam dung chc quyen), phap lenhchong tham nhung, thc hanh tiet kiem, chong lang ph, hay trong cac quy nh totung (thu tuc kham xet, cung cap chng c).

Cac chng c trnh bay t nhng khai niem n gian en phc tap. Mac du au trluan ngay nay c nghien cu nhieu tren khia canh thong tin bat oi xng, chung tanen bat au t mot khung suy luan n gian - thong tin oi xng - ngha la cac chu thebiet ro thong tin ve nhau. o la cach chung toi bat au Chng 1.

Le NetSoan tai London School of EconomicsThang 4-2003


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Chng 1: Quyet nh trong nhng cuoc au tr thongthng

au tr thong thng

Van e n gian nhat trong au tr la nghien cu cach x s gia hai ngi. Moingi phai quyet nh se lam g ma khong phai hoi ngi kia ang lam g. Th du haichiec xe i ngc chieu trong mot con ng nho - mot ngi nen dng e nhngngi kia, lach sang hai phia khac nhau, hay am au vao nhau? Hoac mot ngi ixe gap ngi i bo qua ng th ai nen nhng ai? Neu khong co phap luat, co lemoi ngi se tm cach x s theo y mnh thch. Tuy nhien, do co cac quy nh ve boithng thiet hai do nguon nguy hiem cao o gay ra, ngi i xe phai y thc ma

nhng ngi i bo, cha can biet ai ung luat giao thong, ai sai. Nh vay ro rangphap luat co anh hng oi vi cuoc "au tr" gia ngi i xe va ngi i bo, sao choca hai cung co li.

Tat nhien e phap luat thc s co anh hng, chung ta can mot so giai thiet, o lamoi ngi phai hieu ro cac quy nh cua phap luat, va cac quy nh nay c Nhanc bao am thc thi. Da tren cac gia thiet nay, chung ta co the ap dung au trluan cho nhieu trng hp khac (tn dung, au t, kinh doanh) gia cac chu the. Hophai suy ngh cac x s sao cho co li cho ban than ho, va phap luat phai nghien cucac quy nh sao cho khi cac ben suy ngh ve li ch cua mnh va hanh ong, th ket

qua se la co li cho ca hai ben, ch khong phai ch co li cho mot ben va ben kia bchen ep.

Ban chat cua au tr luan la dung cac mo hnh n gian e khai quat hoa cac hanh vicua con ngi va ly giai tai sao cac ho lai co nhng hanh vi nh vay. Nh vay, sdung au tr luan cung giong nh s dung mot ban o e tm ng i trong thanhpho. Ban o khong can phai chnh xac hay cu the ve toa o ng pho hay khoangcach gia cac con ng, nhng no phai cung cap c cho ngi s dung nhngthong tin can thiet (v du - co may con ng e i t Nha th c ba en San BayTan sn Nhat). Da tren thong tin o ma chung ta ra quyet nh. Phap luat can thiep

vao qua trnh quyet nh nay cung tng t nh thay oi chiec "ban o" trong auchung ta.

e nghien cu mot cuoc au tr (hay con goi la mot tro chi), chung ta can e y enba yeu to:

1) Ngi chi(player).2) Cach chi hay chien lccua tng ngi (strategy).


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3) Ket qua(payoff) cua tng ngi sau khi ap dung cach chi.

Mot cuoc au tr goi la "thong thng" (normal form game) khi no bao gom ba yeu totren, bat ke cuoc au tr nay c tien hanh bao nhieu lan.

Trong cuoc au tr gia ngi i xe va ngi i bo co hai ngi chi. Ngi i xe cohai cach chi: hoac la nhan ga lao ti ngi i bo, hy vong ngi nay se nhng mnh,hoac la phanh lai nhng ngi i bo. Ngi i bo co hai cach chi: hoac bang quang ngay (co the b thng - cha benh het 1 trieu ong), hoac ch ngi i xe iqua (ton thi gian - mat 100 ong). Van e cua cuoc au tr la ca hai phai quyet nhcung mot luc. Ket qua co hai kha nang xay ra: hoac hai ngi am nhau, hoac ca haian toan. Neu phap luat khong can thiep vao cuoc au tr nay, th ket qua se luon coli cho ngi i xe. V the ngi i bo se ap dung mot chien lc duy nhat la nhngngi i xe. Neu phap luat quy nh ngi i xe phai boi thng cho ngi i bo neu

hai ngi ung nhau, ngi i xe se phai suy tnh xem nen tang ga hay giam ga. Doket qua cua cach chi tang ga (co the phai boi thng - 1 trieu ong) thap hn cachchi ap phanh (khong phai boi thng - nhng ton xang - mat 100 ong), ngi i xese chon chien lc nhng ngi i bo. S dung bang e phan tch th chung ta se cocac ket qua (ngi i bo trc, ngi i xe sau) neu ngi i xe khong phai chu trachnhiem ve viec mnh lam nh sau:

Ngi i xeKhong can than Can than

Ngi

i bo

Khong can than -1000000, 0 -1000000, -100

Can than -1000100, 0 -100,-100

Theo bang phan tch th cach chi co li nhat cho ngi i xe trong trng hp tren la"khong can than" Khai niem cach chi luon co li nhat trong moi trng hp cgoi la "chien lc toi u" (dominant strategy). nh ngha au tien ve au tr la: ngichi se chon chien lc toi u bat c luc nao kha nang cho phep va se khong chonchien lc ma ch co li cho phia ben kia.

Ngi i bo biet la ngi i xe se khong can than, va tot nhat la mnh nen can than.Tuy nhien o khong phai la chien lc toi u, v neu ngi i xe can than th cach

chi tot nhat cho ngi i bo la khong can than (tiet kiem c 100 ong). Nh vayngi i bo khong co chien lc toi u tuyet oi, ma chien lc cua anh ta se tuythuoc vao chien lc cua ngi i xe. Tat nhien khi ngi i bo biet chien lc toi ucua ngi i xe la "khong can than" anh ta se chon "can than." Cach suy luan nay batau cho mot khai niem goi la toi u lap lai(iterated dominance): ngi chi gia thietrang ben kia se chon chien lc toi u, va se co phan ng da tren gia thiet nay.Ngi kia cung da tren phan ng nay ma co bien phap oi pho tng ng. en lt


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ngi au tien, anh ta cung phai lap lai gia thiet cua mnh 1 lan na, va c the suyluan en vo cung. Th du: ngi i bo biet ngi i xe khong can than va se phai canthan. Ngi i xe biet ngi i bo se can than va lai cang khong can than. Ngi ibo lai cang phai can than hn, ngi i xe cang khong can than, va c the tiep tuc.Tom lai, moi ngi chi eu cho rang ben kia hanh ong co li nhat cho ho (strictlyrational).

Trong mot cuoc au tr, gia s ca hai biet trc ve hau qua ma hanh vi cua mnhmang lai va biet cach chi cua ngi kia, th cuoc au tr nh vay la hoan chnh(vehau qua) va tuyet oi(ve thong tin) - complete and perfect information. Neu ngichi ch biet trc hau qua nhng khong biet cach chi cua ngi kia th cuoc au trla hoan chnh khong tuyet oi(complete but imperfect information). Neu ho khongbiet c ca hau qua lan cach chi th cuoc au tr la khong hoan chnh va khongtuyet oi(incomplete and imperfect information).

Thay oi ket qua e thay oi chien lc cua ngi chi

Cho du ngi i bo co can than, anh ta van co kha nang b ngi i xe am phai.Cach co li nhat cho ca hai ben la ca hai cung phai can than, nhng e bao am ayse la cach chi ca hai cung la chon, can phai co s can thiep cua phap luat. Bangcach quy nh ngi i xe phai boi thng ngi i bo, khoan tien 1 trieu ong sec chuyen t ngi i bo (thiet hai) sang ngi i xe (tien boi thng thiet hai) vabang phan tch se tr thanh:

Ngi i xeKhong can than Can thanNgii bo

Khong can than 0, -1000000 0, -1000100Can than -100, -

1000000-100,-100

Nh vay thay oi quy nh cua phap luat co the lam thay oi hanh vi cua chu theva"giai quyet cuoc au tr" (solution concepts), cho du la cung mot hoan canh s viec.Khi nay ngi i bo co chien lc toi u (khong can than). Neu ngi i xe trong moitrng hp, he ung phai ngi i bo, eu phai boi thng cho du la do loi cua ngi

i bo, anh ta se co chien lc toi u la khong can than, va chac chan se am phaingi i bo. Nh vay cach giai quyet cua phap luat trong trng hp nay khong phaila toi u.

Trong cuoc song chung ta gap rat nhieu trng hp quy nh thieu can bang nh vay.Th du Phap lenh cong chc quy nh rat nhieu ve cach thi tuyen cong chc, nhng laikhong quy nh chat che khi nao th cong chc b sa thai khoi ngach. Nh vay ngi


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lam viec hp ong se no lc e thi vao ngach cong chc, nhng sau o se thieu no lctrong cong viec. Tng t, Ngh nh ve au t trong nc quy nh he san xuat kinhdoanh mot so nganh nge th c u ai thue, nhng lai khong quy nh khi t y giaithe trong thi han c hng u ai th phai hoan tra cac khoan u ai cho nha nc.ieu nay se tao ra ke h cho doanh nghiep li dung. Mot th du na la cac quy nhve to chc hoat ong cua mot so c quan nha nc quy nh rat nhieu ve quyen han,nhng lai khong quy nh trach nhiem neu l la khong thc hien quyen han cua mnh.ieu nay lam nay sinh c che xin-cho: mot ben ch co quyen ma khong co ngha vu,va ben kia th ngc lai.

Tr lai vi cuoc au tr gia ngi i bo va ngi i xe. Phap luat co the giai quyettheo hng ngi i bo ch c boi thng neu anh ta a can than va ngi i xekhong can than. Bang phan tch gi ay tr thanh:

Ngi i xeKhong can than Can thanNgii bo

Khong can than -1000000, 0 -1000000, -100Can than -100, -

1000000-100,-100

Trong trng hp nay, ngi i bo co chien lc toi u la "can than," trong khi ngii xe khong co chien lc toi u. Neu ap dung cach suy luan toi u lap lai, th ngii xe se phai can than (e khong b boi thng). Tuy nhien ay cung cha phai la toiu, v ke ca khi ca hai cung can than, th ngi i xe van co the am vao ngi i bo,

nh vay ngi i bo se khong dam ra ng, va o cung khong phai la ieu phap luatmong muon. Trong cuoc song chung ta cung gap nhieu quy nh "qua ta" nh vay.Th du Thong t 825/2000 cua Bo Khoa hoc Cong nghe Moi trng qui nh neu cquan thc thi quyen s hu tr tue ma gay nen thiet hai cho oi tng b thc thi thphai boi thng. ieu nay se lam cho cac c quan phai can than khi thc thi. Nhngneu "qua can than" se dan en ngai thc thi, va van nan xam pham quyen s hu trtue khong c giai quyet.

e tm cach giai quyet toi u, phap luat co the quy nh rang ngi i xe phai boithng trong moi trng hp am phai ngi i bo, tr khi ngi i bo hoan toan co

loi. o cung la quy nh ieu 627 BLDS. Bang phan tch gi ay tr thanh:

Ngi i xeKhong can than Can than

Ngii bo

Khong can than -1000000, 0 -1000000, -100Can than -100, -

1000000-100,-200


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Ket qua co thay oi so vi bang phan tch trc o, v ngi i xe phai can than hn(phai kiem tra phanh trc khi i, va phai tap trung cao o khi lai xe e loai tr moikha nang xay ra). Tuy nhien oi lai ngi i bo se an tam hn khi ra ng. Nh vaythay oi quy nh cua phap luat co the lam thay oi hanh vi cua chu the tham ch cakhi ket qua t thay oi. Tr lai th du cua Thong t 825. Thay v quy nh c quan thcthi phai boi thng, co the quy nh c quan thc thi ch boi thng khi do loi co y cuamnh gay ra.

iem can bang Nash

cuoc au tr tren, chung ta co the ket hp hai giai phap (ngi i xe ch boi thngneu co loi va ngi i xe phai boi thng tr trng hp loi hoan toan thuoc ve ngii bo) bang 1 giai phap trung hoa. o la tien boi thng se c giam theo t le loi.

Th du neu ca hai tng oi (hi) can than hoac eu khong can than, moi ben se chumot na tien thiet hai. Chi ph cho viec "hi" can than la 50 ong. Bang phan tch setr thanh:

Ngi i xeKhong can than Hi can than Can than

Ngii bo

Khong can than -500000,-500000 -1000000,-50 -1000000, -100Hi can than -50,-1000000 -500000,-500000 -1000050,-100Can than -100,-1000000 -100,-1000050 -100,-200

Khi nay, ca hai ben eu khong co chien lc toi u tuyet oi, ma ch co toi u tng

oi. Neu 1 ben chon cach chi "khong can than", ben kia se co chien lc toi utng oi la "hi can than." Tuy nhien neu ap dung suy luan "toi u lap lai," th benau tien se khong bao gi chon "khong can than" (v nh the ch co li cho ben kia),ma anh ta se phai chon "can than." Tng t ben kia biet vay se chon "can than."Nh vay "can than" se la ong chien lc toi u cho ca hai ben. Chien lc nay la toiu cho moi trng hp ma ben kia chon. Cach giai quyet nay goi la can bang Nash(Nash equilibrium), ngha la chien lc an toan nhat oi vi moi s la chon cua oiphng. ay la nh luat quan trong nhat cua au tr luan. Tm iem can bang Nashla tm c bai giai cua cuoc au tr, bi v neu li giai khong v tr can bang thmot trong cac ben se li dung s bat can bang e thay oi chien lc. Theo o, benkia cung phai co oi phap tng ng. C "toi uu lap lai" nh vay chung ta se phai tienen iem can bang Nash, tng t nh con lac dao ong cho en khi can bang.

Tuy nhien khong phai moi trng hp ch co mot chien lc an toan nhat. Co nhieucuoc au tr khong co chien lc an toan nhat, ma co nhieu chien lc an toan tngng. Ta goi o la cac iem can bang Nash (Nash equilibria). Cuoc au tr "anh vaem" (battle of the sexes) la mot th du. Nam (anh) va Mai (em) d nh i chi ngay


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3) Cac nhan to ngoai lai se khong lam thay oi ket qua tr s tac ong cuaphap luat, va ngoai cac d kien ma chung ta biet khong con d kiennao khac e lam thay oi chien lc cua cac ben. Gia thiet nay trongkinh te goi la ceteris paribus.

Muc ch cua cac gia thiet la e n gian hoa bai toan ve au tr. Tuy vay ieu naykhong co ngha la au tr luan khong ap dung c trong thc te. Trong toan hoc, cacbai toan phc tap co the c qui ve cac dang n gian bang cach c lc hay at anso phu. Khoa hoc xa hoi phc tap hn khoa hoc t nhien cho so lng bien so va anso nhieu hn, nhng khong can phai chnh xac giong nh khoa hoc t nhien. Cai makhoa hoc xa hoi, trong o co phap luat, giai quyet - la tm ra c hng ung e i.Vi cach nhn nh vay, au tr luan la mot cong cu hu dung e tm hieu hanh vi vamoi quan he gia ngi vi ngi, tren c s o ieu chnh chung cho phu hp vi ych cua phap luat.

Quy nh cua phap luat va khai niem toi u hoa

Tr lai cuoc au tr gia ngi i xe va ngi i bo, chung ta thay phap luat co theieu chnh sao cho ho cang can than th cang t phai chu trach nhiem dan s. Nghala "can than" phai tr thanh chien lc toi u duy nhat cho ca hai ngi. Khi mottrong hai ben t can than, kha nang ho se phai boi thng thiet hai cao hn, nh vayho phai biet suy tnh macan than hn. Tat nhien khi ca hai cung can than th khanang xay ra am nhau cung t hn, va v the cach giai quyet nay co li nhat cho ca haiben va cho ca xa hoi. Khi mot trong hai ben "qua can than", ho se nhan ra rang ho

ch lam tang chi ph cho viec nay ma khong em lai hieu qua g hn la "can than." Vthe ho se t ieu chnh mc can than tng ng vi phia ben kia.

Neu 1 ben tm ra c mot chien lc toi u khac th ket qua se ngc lai vi nhngg phap luat mong muon. Trong trng hp nay chung ta noi phap luat khong co hieuqua (khong toi u hoa cach x s cua moi ngi). Tom lai phap luat ieu chnh cohieu qua nhat la khi no hp long ngi - hay chung ta goi la "khi day cac nguon lctrong xa hoi." Luat doanh nghiep ban hanh nam 2000 la mot trong nhng v du nhvay. Luat a khi day ban chat nang ong tm c hoi lam giau cua moi ngi. Saukhi luat ra i, hang chuc nghn doanh nghiep a c thanh lap, tao ra cong an viec

lam cho hang trieu ngi dan, mot viec ma neu Nha nc ch giai quyet bang au ttrc tiep th se ton rat nhieu tien cua ma khong co hieu qua bang. Trong khi o viecgiai quyet nan un tac giao thong TP. Ho Ch Minh lai la mot phan v du. Nam 1998UBND Thanh pho giao cho cong ty xay dng m rong ng ien bien phu - dai2km. Theo tieu chuan quoc te th xay dng 2km ng ch het t 2 en 3 trieu USD.Trong khi o gia thanh xay dng thc te la 5,5 trieu USD, va tien en bu la 100 trieu


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USD (chien 50 phan tram ngan sach xay dng c ban cua thanh pho!).1 Cach giaiquyet nh vay khong co hieu qua, trong khi e giai quyet nan un tac giao thong Nga t Phu nhuan hay Nga t Bay hien ch can phan luong giao thong va ieu chnhgi i lam la a co ket qua ro ret. Neu UBND Thanh pho nghien cu ky cach sdung ng pho cua ngi i ng (chien lc toi u cua ho), so sanh ket qua apdung chnh sach (m rong ng hay ieu chnh bang phap luat) th a co the tranhlang ph mot khoan tien ln cho ngan sach.

Cuoc au tr gia hai ngi chi khong co y nh cong tac

Tren thc te, phap luat phai giai quyet nhieu van e phc tap hn la cuoc au tr giangi i xe va ngi i bo. Th du trong viec tm a iem xay dng Nha may loc dauso 1 cua Viet nam, hay chon giai phap noi Quan 1 vi Thu Thiem (lam ham hay baccau), chung ta phai tnh en nhieu yeu to. Khong ch hieu qua kinh te ma con hieu

qua xa hoi va nhng li ch lau dai i kem. Tuy nhien thong thng cac cuoc au trphc tap o eu co the c giai quyet bang cach qui ve cac dang au tr n giangia hai ngi vi nhau. Ngi ta phan cac cuoc au tr nay thanh hai dang: au trgia nhng ngi chi khong co y nh cong tac(non co-operative game) va au trcua nhng ngi chi co y nh cong tac(co-operative game).2 Trc ay Mao Trachong cung phan biet cac loai mau thuan thanh mau thuan noi bo (co-operative game)va mau thuan ch-ta (non co-operative game).

au tr gia ngi i xe va ngi i bo la au tr gia hai ngi khong co y nh congtac. Neu khong co phap luat quy nh th ngi i xe se ch hanh ong sao cho co li

nhat cho mnh bat ke hau qua gay ra cho ngi khac. Mot th du la nan ua xe trcay cung vay. Do che tai qua nhe lai thc thi khong nghiem, nen mac du lc lngcanh sat ton rat nhieu cong sc nhng van khong dep bo c te nan nay. Ke t khico quy nh se tch thu cac xe may tham gia ua xe ban lay tien ho tr cho qu giup ngi tan tat, nan ua xe a giam han. Nh vay e giai quyet cuoc au tr gia nhngngi khong co y nh cong tac, can phai tm ra li ch chungcho hai ngi neu hocong tac hay moi e doa chungneu ho khong cong tac. Trong cuoc au tr gia ngii xe va ngi i bo, moi e doa chung cua ho la nhng thiet hai ve kinh te neu hokhong tuan thu phap luat.

Neu cac ben khong co mot li ch chung hay moi e doa chung nao, ho se ngh enchuyen li dung nhau. Neu chung ta ap cach suy luan "toi u lap lai", th ca hai sengh en chuyen li dung lan nhau va ket qua se bat li cho ca hai. Mot th du c banve au tr gia hai ngi chi khong co y nh cong tac la au tr "nghi pham"(prisoner's dilemma). Hai nghi pham trong mot vu cp ang trong qua trnh ieu

1Bao Quan oi Nhan dan ngay 9-4-2003.

2Binmore, K. (1996) Selective Essays on Game Theory. MIT Press.


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tra. Muc ch cua ieu tra vien la lam sao cho ca hai nhan toi. e thc hien ieu nay,ieu tra vien cach ly hai nghi pham hai phong khac nhau, va thong bao rang neu cahai cung nhan toi, moi ngi se b tuyen an 6 nam tu. Neu mot ngi nhan toi conngi kia khong nhan toi, ngi nhan toi se c khoan hong, con ngi "ngoan co"se b phat 10 nam tu. Neu ca hai cung khong nhan toi th moi ngi se chu 2 nam tu.Xet ve li ch cua cac nghi pham th tot nhat la ho khong nen nhan toi. Tuy nhien vho khong c noi chuyen vi nhau nen khong biet ngi kia se noi g vi ieu travien. Ho khong muon khong nhan toi roi phai ngoi tu 10 nam trong khi ngi kiaphan boi lai ho va c tha. Bang phan tch se cho ta thay ket qua nh sau:

Nghi pham 2Im lang Nhan toi

Nghipham 1

Im lang -2, -2 -10, 0Nhan toi 0, -10 -6,-6

Trong cuoc au tr tren, cac nghi pham se phai tm chien lc an toan nhat cho mnhkhi biet ngi kia ch ngh en quyen li cua ban than ho. Neu nghi pham 2 im langth oi sach tot nhat cua nghi pham 1 la nhan toi. Ngc lai neu nghi pham 2 nhan toith oi sach tot nhat cua nghi pham 1 cung la nhan toi. Nh vay chien lc toi u cuanghi pham 1 la nhan toi. Suy luan tng t cung ap dung cho nghi pham 2. Cuoi cungiem can bang Nash cua cuoc au tr la ca hai cung nhan toi, chu 6 nam tu.

Ket qua tren co ve hai hc, song thc te lai la chuyen xay ra nhieu trong thc te,nhat la oi vi viec khai thac tai san cong cong (public good) ma Hardin goi la te nan

"cua cong khong ai lo"(tragedy of the common). Th du ngi dan Ban Me thuot cohai kha nang - mot la pha rng lam ray (tng ng vi "nhan toi" trong cuoc au trngi tu), va hai la bao ve rng (tng ng vi "im lang"). Neu mot ngi pha rngcon ngi kia bao ve rng, th ngi bao ve rng cung khong c li g, con ngipha rng th c li. Neu ca hai cung bao ve rng th o la giai phap toi u, song vkhong ai tin la ngi kia se khong li dung mnh nen cuoi cung moi ngi se batchc nhau pha rng (neu phap luat khong can thiep). Chung ta cung de dang nhanthay au tr "nghi pham" xuat hien nhieu trng hp khi phap luat khong can thiephay can thiep khong co hieu qua. Th du: gia cac cong chc thoai hoa bien chat(nhan hoi lo hay khong nhan hoi lo), gia nhng ngi dan trong mot khu du lch (xa

rac hay khong xa rac), ngi xem phim VCD (mua a goc hay ia sao chep lau).Tam ly chung cua nhng ngi nay la: neu mnh lam tot th cung chang c li chg, v the tai sao khong i theo chieu hng xau. T cho mot ngi co hanh vi xaunhng khong b trng phat se tao tien le e nhieu khac noi theo va hanh vi xau nay setr thanh nhng hanh ong cua tap the(collective action). Nhieu vu an hnh s ve toitham nhung c xet x, trong o co trng hp ca mot n v thoai hoa bien chat lanhng th du ien hnh ve hanh ong tap the.


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Cuoc au tr gia hai ngi chi co y nh cong tac

Trai vi cuoc au tr gia nhng ngi khong co y nh cong tac, nhng ngi co ynh cong tac cung phai au tr vi nhau trong hai trng hp: hoac la ho phai la

chon mot trong hai iem can bang Nash, hoac ho phai xem ngi kia hanh ong thenao e co oi sach tng ng.

au tr "anh va em" nh a trnh bay tren la dang au tr th nhat. ay Nam vaMai thong nhat la se cung i chi vi nhau (can bang Nash), cai ma ho phai quyetnh la nen i xem a bong (Nam co li hn) hay i mua sam (Mai co li hn). Tongli ch cua ca hai ngi la mot hang so khong oi (5 + 3 = 8). Khi mot ngi c lihn 2 n v th ngi kia kem 2 n v. Hai giai phap can bang Nash tng ngcho ca hai ngi, nhng khong tng ng cho tng ngi. Cuoc chi nh vay goi laau tr hang so(zero-sum game). Khi nay ca hai Nam va Mai ch co mot chien lc

duy nhat(pure strategy equilibirum).

Dang au tr th hai la au tr bien oi(non zero-sum game) va khi nay hai ngi chikhong ap dung mot chien lc duy nhat, ma linh ong ap dung nhieu chien lc khacnhau, tuy vao ngi kia se s dung chien lc g. Chien lc nay c goi la chienlc linh ong- mixed strategy equilibrium). Mot thi du la cuoc au tr "san hu."Hai ngi th san can hp tac vi nhau e san 1 con hu. Neu san c, ca hai sechia oi li tc, moi ngi 10 n v. Tuy nhien e san tho th khong can phai en haingi, va li ch cua ngi san tho la 8 n v. Gia s ang trong luc san hu th motcon tho xuat hien. Neu 1 ngi bo hu san tho th ngi kia se khong bat c hu.

V the ngi th hai cung phai bo hu san tho, va hai ngi se chia chung con thobat c (moi ngi 4 n v). Bang phan tch cuoc au tr nay nh sau:

Th san 2Hu Tho

Th san1

Hu 10, 10 0, 8Tho 8, 0 4, 4

Theo bang tren, ca hai ngi th san cung phai ap dung chien lc linh ong. Th san1 ch san hu neu th san 2 cung san hu, con ngc lai ca hai se cung san tho. Tatnhien sau khi chia oi con tho bat c, ca hai se khong hai long, va thoa thuan lansau se cung san hu. Nh vay trong cuoc au tr nay khong co g chac la moi th sanse ap dung mot chien lc duy nhat.

Neu tnh xac suat cac lan san chung ta se co ket qua chnh xac la kha nang nao sexay ra nhieu hn. Th du goi p1 la xac suat san hu cua ngi th nhat, 1 - p 1 la xac


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suat san tho, th tong hai xac suat se la: EPV (expected profit value) = 10p 1 + 8(1-p1)= 8 + 2p1 > 8 > 4 (li ch khi ca hai cung san tho). Th vay cho du la chon xac suatthe nao th s dung chien lc linh ong cung tot hn la ch ap dung mot chien lcduy nhat la san tho. Tuy vay neu ch ap dung chien lc san hu th co kha nang seb ngi th hai li dung khi ngi nay quyet nh "anh le." Sau khi tnh toan xacsuat, ca hai th san co the se i en cung mot ket luan la nen gianh 1 na thi giansan hu va mot na thi gian san tho. Ket luan nay goi la trung iem(focal point)hay iem Schelling.

au tr "san hu" the hien kha nhieu trong cuoc song. Trong van e phong thu quocgia, ieu nay the hien qua cau noi cua Mao Trach ong "ngi khong ung en ta, thta khong ung en ngi" (ca hai se ap dung cung mot chien lc). Trong kinhdoanh, ieu nay the hien qua viec thanh vien to chc xuat khau dau mo the giiOPEC quyet nh tang hay giam san lng dau. Neu OPEC quyet nh giam san

lng, ma mot trong cac thanh vien nh "anh le" bang cach tang san lng dau, thA-rap Xe-ut se tang san lng dau tng ng, lam giam gia dau va giam doanh thucho nc "anh le." Trong th trng chng khoan cac tay chi chng khoan nho baogi cung quan sat ong thai cua cac tay chi chng khoan ln e co oi sach tng t.Th trng nong san cung vay, va vu kien ca ba sa la mot th du. Hiep hoi thuy san(VASEP) ch co the theo uoi vu kien neu toan bo cac thanh vien nhat tr, neu khongho se khong theo uoi vu kien ma se tm cach thng lng vi Hiep hoi nghe ca My(CFA). iem sai lam cua VASEP la a tin rang Bo thng mai My (DOC) se ra phanquyet cong bang. V DOC la mot c quan chnh phu, ho co quyen li trong viec danhc cam tnh cua ngi dan My - cu the la CFA. o la nhng ngi se bo phieu bau

Tong thong - anh hng gian tiep en bau bo trng Thng mai. Nh vay kha nangDOC co the "lay long" CFA e kiem phieu bau nhieu hn la se cong tac vi VASEPtren tinh than thien ch. V cuoc au tr gia VASEP va DOC la au tr gia hai ngikhong co y nh cong tac (DOC khong can phai cong tac vi VASEP), nen iem coli cho ca hai ben la khong co. Ngc lai, neu VASEP tac ong Vietnam Airlineshoan hp ong mua 4 may bay Boeing 777 cua My va gan viec nay vi thoa thuan veca ba sa, DOC se cong tac vi VASEP tot hn. Nh vay, cac nha hoach nh chienlc co the chuyen mot cuoc au tr t au tr "bat cong tac" sang au tr "cong tac"bang cach gan ket cac quyen li vi nhau.

Chien lc linh ong the hien ro nhat trong au tr "sap nga"(matching the pennies).Hai ngi chi tung ong xu. Mot ngi tung va up ong xu lai, hoi ngi kia "saphay nga?" Neu oan ung ngi o se c 10.000 ong, oan sai se mat 10.000ong. Chien lc tot nhat cho ngi oan la "linh ong" va oan sap va oan nga- v xac suat cua moi trng hp la 50%. Mot th du trong cuoc song ve viec ap dungchien lc linh ong la viec bat toi pham ma tuy. Gia s cac chien sy cong an biet hem X hay dien ra mua ban ma tuy. Ho co hai cach la chon - mot la cam chot 1


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chien sy cong an hem X, hai la thnh thoang phuc kch bat nhng ke buon ma tuy.Chien lc th nhat se khong co hieu qua, v nhng ke buon ma tuy se chuyen iaiem sang cho khac, trong khi chien lc th hai co the thu c ket qua kha quanhn.

Mot dang khac cua chien lc linh ong la au tr "ga mai"(chicken game). Trongtran au tren khong au tien cua khong quan Viet nam nam 1964, hoan canh sau aya dien ra: mot chiec may bay Mig-17 cua Viet nam het an va b mot chiec may bayF-4 cua My uoi theo. Anh a quay ngc chiec may bay cua mnh lao thang vaochiec F-4. Co 4 kha nang xay ra: Mig-17 va F-4 cung am vao nhau. Mig-17 thangva F-4 bo chay (F-4 se b goi la ke hen nhat hay "ga mai"), Mig-17 chay va b F-4ban chay, hay ca hai cung tranh nhau. Thc te a dien ra ung nh d oan: chiec F-4tr thanh "ga mai" va bo chay ma khong he biet chiec may bay cua ta a het an.Trong cuoc au tr nay co hai iem can bang Nash: mot co li cho chiec Mig-17 va

mot co li cho chiec F-4. Xet ve mat tong the th chung tng ng nhau, nhng oivi ngi chi th ngi dung cam nhat, giam chu rui ro nhat se la ngi chien thang.Trong kinh doanh cung vay. Chnh phu phai quyet nh xem Viet nam co nen thamgia lch trnh mien giam thue ASEAN (NAFTA) hay gia nhap WTO hay khong. Congi cho rang Viet nam cha u ieu kien e hoi nhap v sc canh tranh cua Vietnam qua yeu (giong trng hp chiec may bay Mig-17 cua Viet nam b het an phaioi choi vi phi oi F-4 cua My ong hn va manh hn nhieu lan). Tuy nhien neuViet nam dung cam m ca va cac doanh nghiep trong nc chap nhan canh tranh vidoanh nghiep nc ngoai, th sc canh tranh qua tng lan co xat vi thc te se cnang len. Ngc lai neu Viet nam ngai hoi nhap, sc canh tranh cua cac doanh

nghiep trong nc cang yeu va sm muon g cung se b cac cong ty nc ngoai lan at.Nh vay luat phap - thong qua cac quy nh t do hoa thng mai - co the thay oi sccanh tranh cua doanh nghiep trong cac cuoc au tr vi cac cong ty nc ngoai.

Mac du au tr co the giup ch rat nhieu trong kinh doanh cung nh trong viec banhanh va ap dung cac van ban phap luat, chung ra cung khong nen khai quat mot cachvoi va rang bat ky moi quan he xa hoi nao cung co the qui ve mot trong hai cuoc autr - "nghi pham" hay "anh em." Cac ket luan t trc en gi nay da tren gia thietla ca hai ngi chi ch au tr mot lan va co ay u thong tin ve nhau. Thc te khonghan la nh vay. Trong cac chng ti chung ta se xet en nhng trng hp cac ben

khong co thong tin hoan chnh ve ket qua cung nh chien lc cua ben kia, hoac motben tham gia vao nhieu cuoc au tr cung mot luc vi nhau.

Ket luan


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au tr luan, thong qua hai cong cu la bang phan tch va iem can bang Nash a thehien la mot cong cu hu hieu giup chung ta phan tch anh hng cua phap luat enhanh vi cua cac chu the, ong thi tm giai phap can thiep toi u bang phap luat vaomot van e. e phan tch, chung ta can qui nhng van e phc tap ve mot dang ngian ien hnh va ch phan tch nhng iem quan trong nhat, nham tm ra hng giaiquyet van e. Trong chng nay, chung ta a lam quen vi hai dang au tr thongthng: o la au tr gia hai ngi co y nh cong tac (co-operative game) va haingi khong co y nh cong tac (non co-operative game). Muc tieu cua phap luat lakhong nhng lam cho cac cuoc au tr thanh cac cuoc au tr co y nh cong tac, ma ynh cong tac o phai the hien chien lc toi u va an toan nhat cho cac ben tham gia.

e co the ap dung au tr luan va phan tch mot van e, can lu y cac iem sau ay:

1) Ban chat cua cuoc au tr gia cac ben la "cong tac" hay "bat cong tac" (xem

vu kien ca basa). Neu chung bao gom ca cong tac lan bat cong tac, th xemiem nao co the cong tac c, va iem nao khong the cong tac c (xemau tr "nghi pham").

2) Sau khi xem ban chat cuoc au tr, can tm xem trong cac mo hnh au tr, mohnh nao the hien ro nhat thc chat van e. Th du trong mo hnh au tr congtac co au tr dung mot chien lc duy nhat ("anh-em"), au tr dung chienlc linh ong ("san hu" hay "sap nga"), hay au tr vi tinh than san sangchap nhan rui ro ("ga mai").

3) Dung au tr luan co the ieu chnh cac iem can bang Nash cuac cac bentrong tng trng hp, sau o la chon giai phap phu hp vi y ch cua cac nhalam luat. Tuy nhien ap dung sai mo hnh au tr co the dan en ket luan sai vagiai quyet van e sai.


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Chng 2: Moi tng quan ong va cac cac cuoc autr m rong

au tr m rong va phng phap "qui nap ngc"

Trong chng trc chung ta a phan tch au tr thong thng (normal form game).Mot dang au tr na la au tr m rong(extensive form game), trong o ngi chikhong co ay u thong tin ve cach chi cua nhau,va cung khong thc hien cac chienlc ong thi vi nhau, giong nh anh bai hay anh c. Cac ng dung cua loai autr nay kha nhieu. Th du lam the nao e ngan hang co the biet c co nen cho motngi khong co bao am vay tien hay khong, lam sao biet c mot doanh nghiepang thc hien cac hanh vi oc quyen. Hai cong cu cua au tr m rong la phng

phap qui nap ngc(backward induction - hay "luan co suy kim") va au tr th caphoan chnh(subgame perfection). Muc ch cua viec s dung cac cong cu nay la tmthong tin ve chien lc cua oi tac va co au phap tng ng. Cac nhan to tham giatrong cuoc au tr m rong bao gom:

1) Ngi chi.2) Thi iem chi (thc hien chien lc) cua tng ngi.3) Kha nang chon la cua moi ngi vao tng thi iem.4) Thong tin ma ngi chi co c tng thi iem.5) Ket qua chi oi vi tng cach chi.

e phan tch au tr m rong ngi ta khong dung bang ma dung s o hnh cay, theoo moi thi iem chi la mot ot(node). T mot ot au tien(initial node) phat sinhcac kha nang chi khac nhau, goi la canh (branch). Cuoc au tr ket thuc tai iemngon(terminal node), luc o moi ngi chi mi co ket qua sau cung. Ngc lai, neutai iem nay ngi chi tiep tuc au tr (vi ngi cu hay vi ngi mi) th iem oc goi la ot quyet nh (decision node). Th du cuoc au tr gia ngi i xe vangi i bo khi khong co phap luat can thiep dien ra nh sau (ngi i xe chi trc):

Ngi i xe

(0, 1 trieu)

Bat can

Ngi i bo

Bat can Can than

Can thanBat can

Can than

(0, - (-100, -1 trieu)

( 100, 100)


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Khac vi au tr thong thng, ngi i bo trong trng hp nay biet c ngi i xese lam g va co au phap tng ng. Vao th iem anh ta phai hanh ong, ngi ibo co trong tay mot so thong tin(goi la information set). Da tren thong tin nay maho chon au phap. Neu ngi i xe phong nhanh va nhn thay ngi i bo, anh ta sed oan xem phan ng cua oi phng la g. Neu ngi i bo van bang qua ng,anh ta co hai s la chon, hoac tiep tuc phong nhanh, hoac phanh lai. Vao thi iemo, ngi lai xe co nhieu thong tin e chon la chnh xac hn khi cha nhn thay phanng cua ngi i bo.

Trong thc te co nhieu trng hp mot ben phai ch ben kia boc lo thong tin roi mico the ra quyet nh. Th du trc khi nhan vao lam viec chnh thc, ngi lao ongphai qua mot giai oan th viec. Trong o ngi s dung lao ong giao viec trc (otau tien), ngi lao ong phan ng sau. Sau khi co c thong tin ve ngi lao ong,ngi s dung lao ong mi quyet nh co nen ky hp ong lao ong chnh thc hay

khong. Tng t trong hp ong mua sam: khi cha biet chat lng hang hoa hay dchvu th khong nen ky hp ong ln hay dai han, ma phai co quyen s dung th trc,neu co hieu qua mi tien ti s dung nhieu va lau dai. Trong hp ong dau kh cungvay. Cong ty khoan dau ch quyet nh au t nhieu sau khi a tham do thay dau vasan lng dau u e khai thac thng mai. nc ta mot so hp ong mua sam ln(may bay, tau thuy, thiet b mang ien thoai vien thong) a chu lo hay kem hieu quala do ngi mua cha kiem nh chat lng va nang suat cua vat mua tren thc te, malai qua tin vao nhng quang cao cua ngi ban.

Xet th du ve cuoc au tr gia ngi cho vay va ngi vay ve mot khoan vay 1 trieu

ong. Ngi cho vay muon ngi vay dung tien vay vao ung muc ch va tra lai vay(100.000 ong) va von vay ung han. Tuy nhien khong co g bao am la sau khi nhantien ngi vay se tra von va lai ung han, cho du ho co b kien ra toa. Neu ngi ivay khong chng minh c rang mnh co kha nang tra n, ngi vay co the t choicho vay. Li ha cua ben vay cung khong ang tin cay(credible) neu khong co ongc nao e cho ben vay gi li ha. Neu phap luat khong bao am cng che ngivay, th ngi vay co the nuot li ha va s o au tr se c the hien nh sau:

Ben cho vay

Ben vay

Khong cho vay Cho vay

(0, 0) Khong tra Tra n

(1 trieu, 1300000)(100.000, 100.000)


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Gia s ngi vay vay tien e kinh doanh va lai 200.000 ong. Neu anh ta khong tran th se c li 1.300.000 ong (1 trieu ong tien von, 100.000 ong lai vay va200.000 ong li nhuan). Neu tra n th se ch c li 100.000 ong (200.000 ongli nhuan tr i 100.000 ong tien lai). Nh vay ngi vay se chon giai phap khongtra n. V biet vay nen ap dung phng phap qui nap ngc, ngi cho vay se quyetnh khong cho vay. e giup ngi cho vay co the yen tam vay tien va ngi vay cotien e san xuat, khong nhng can co luat ma he thong am bao thc thi luat phai cohieu qua va san sang giup doanh nghiep. Ben canh o luat pha san phai thc s ivao cuoc song e tai san cua ngi vay de dang. Mot khi co s tr giup cua phap luat,cac ben de dang thiet ke chien lc an toan va toi u cho mnh. iem can bang Nashtrong hp ong vay se la ngi cho vay xuat von va ngi vay tra von lan lai chongi cho vay.

Trong thc te, chuyen n kho oi cac doanh nghiep Viet nam hien nay cung mot

phan la do c quan thi hanh an qua tai va khong u ngi e thi hanh het cac ban anoi n can thiet. Lau dan ch tn trong kinh doanh thap se dan en giam sc canhtranh cua nen kinh te. Nam 2002 Viet nam xep th 65 trong tong so 72 nc cnghien cu tren the gii ve sc canh tranh, va mot trong nhng iem yeu nhat cuaViet nam la c che thc thi phap luat (xep th __ trong tong so __ nc). 3 Nhng thdu ien hnh cua he thong thc thi yeu bao gom: qua t cac phan quyet cua trong tainc ngoai c cong nhan tai Viet nam, cac khoan n kho oi khong c hoan tra,va t le an ton ong cac toa an cung nh quyet nh thi hanh an ton ong phongthi hanh an.

Phng phap "phong nga" va cac cam ket chien lc

Trong cuoc au tr khi mot ben i trc, ho co iem bat li la phai thong tin cho benkia biet chien lc cua mnh. Tuy nhien ho co u the la khong b anh hng bi cacthe tran ma ben kia tao ra, ong thi co the gai ben kia vao the tran ma mnh dngnen. Hai loai the tran nay la the tran "phong nga" (preemption) va cam ket chienlc(strategic commitment). Mot th du ve the tran phong nga la vu Uy ban Thngmai My (FTC) kien DuPont de Nemours & Co. DuPont chiem bang sang che ocquyen san xuat titan dioxit, chat tao mau trang cho sn va nha. Do vay ho a "itrc" cac oi thu canh tranh khac hang chuc nam. Khi cac oi thu canh tranh khac

tien vao th trng, DuPont a tien hanh mot so bien phap nh giam gia e anh baioi thu, hay m rong c s kinh doanh ti mc oi thu khong con th trng e phattrien. Bang cach cho oi thu canh tranh biet rang DuPont san sang tieu diet ho,DuPont a bien s e doa cua mnh tr nen ang s (credible threat) va la cam ketchien lc oi vi oi thu canh tranh. Tien xa hn DuPont co the tien hanh cac bien

3Xem World Economic Forum 2002.


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phap phong nga nh lap ay cac khoang trong tren th trng ngay ca khi cac oi thucanh tranh cha kp at chan vao th trng. Chung ta cung co the gap mot th dutng t Viet nam khi Coca-cola va PepsiCo thi nhau ha gia gianh th phan nam1998 (t 2.000 ong /chai xuong con 700 ong/chai). Thc te viec canh tranh nay lacam ket chien lc gia hai cong ty nham ngan chan cac cong ty nho tien vao thtrng nc giai khat.

Chung ta co the xet mot cam ket chien lc nh sau: co hai cong ty trong mot thtrng nc giai khat - cong ty cu (incumbent) va cong ty mi (entrant). Cong ty cuang co li nhuan la 25USD/thang va neu m rong c s san xuat co the em lai linhuan 30USD/thang. Neu cong ty mi tien vao th trng nc giai khat (phng anA) va cong ty cu khong tra ua (ha gia san pham hay thang cng tiep th) th ho sephai chia se 15USD/thang li nhuan cho cong ty mi. Neu ho tra ua bang cach giamgia th ca hai se ch nhan c li nhuan la 5USD/thang. Neu cong ty mi khong tien

vao th trng nc giai khat masan xuat banh (phng an B) th se c10USD/thang li nhuan. Trong trng hp th nhat, cong ty mi i trc, cong ty cuse phan ng da tren chien lc cua cong ty mi, ta co s o nh sau (cong ty mi,cong ty cu):

Nh vay chien lc cua cong ty cu phu thuoc vao thong tin ma ho nam c cong tymi. Neu cong ty mi chon phng an A, th chien lc toi u cho cong ty cu la thuong (thu li 15USD/thang). Neu cong ty mi chon phng an B, th chien lc toi ucho cong ty cu la m rong. Cong ty mi co the the s dung quy nap ngc e xemnen chon phng an nao. Th du ho tin cong ty cu se khong tien hanh cam ket chienlc hay co bien phap ngan chan nao v trong trng hp nay li nhuan cua ho se b

giam mot na. Nh vay cho du cong ty cu co e doa tra ua th s e doa nay cungkhong ang tin. So sanh khoan li gia hai phng an A (thu li 15USD) va B (thu li10USD), cong ty mi se chon phng an A neu c i trc.

Moi chuyen se khac neu cong ty cu i trc. Neu ho quyet nh m rong san xuat,cong ty mi khong the nhay vao cung san xuat nc giai khat (v ch c li 5USD)va se chon san xuat banh (li 10USD). Neu cong ty cu thu ong th cong ty mi se

(10, 30)

M rong

Cong ty cu

Chon B Chon A

Thu onTra ua

Thu ong

(10, 25) (5, 5) (15, 10)


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Trong cong nghiep o to cung dien ra tnh trang tng t. Nam 1997 cong ty Chryslerxin phep au t vao th trng Viet nam, nham ran e cac cong ty khac canh tranhvao th trng nay, tuy nhien khi thay bien phap e doa cua mnh khong co hieu qua,ho a xin rut lui khoi th trng Viet nam.

au tr th cap hoan chnh

Trong phan trc, chung ta phan ln s dung phng phap qui nap ngc e giaiquyet au tr ma khong dung en tnh toan iem can bang Nash, mac du co the thchien c ieu nay. Ly do la v moi ot eu co the lap bang e tnh iem can bang,va nhieu ot se cho ra nhieu iem can bang Nash khac nhau.

Tuy nhien phng phap qui nap ngc khong ap dung c neu ot tiep theo ngichi khong biet ngi au tien a thc hien chien lc g. Tr lai cuoc au tr gia

ngi vay va ngi cho vay. Th du ngi vay khong tra tien va ngi cho vay phaikien. Viec kien tung ton moi ben 1.2 trieu ong. Nh vay thay v moi ben c li 0.1trieu ong neu tuan thu hp ong, ho se lo 1.1 trieu ong khi kien (1.2 trieu - 0.1 trieutien lai oi c n). S dung phng phap qui nap ngc, ngi vay se quyet nhkhong tra n v biet rang ngi cho vay tha mat 1 trieu ong tien von va 100.000ong tien lai con hn mat 1.2 trieu ong tien kien tung e oi lai 1.1 trieu ong. Bietc ieu nay, ngi cho vay se quyet nh khong cho vay. S o c ghi nh sau:

ay chien lc cua ben cho vay la khong cho vay, hoac neu co cho vay roi mangi vay khong tra n th anh chu mat tien. Chien lc cua ben vay la khong tralai tien. Tuy nhien neu tnh toan iem can bang Nash th chung ta se khong thay ieunay, v chien lc vay va tra n ay u van em lai ket qua tot ep hn (moi benc 100.000 ong) so vi khong cho vay (khong ben nao c g). Tng t, ben vaynen tranh b kien (v phai chu chi ph 1.2 trieu) va tra tien (con c vay lan sau).

Ben cho vay

Ben vay

Khong cho vay Cho vay

(0, 0) Khong tra Tra n

(-1,1 trieu, 1,1 trieu)

(100.000, 100.000)Kien

Khong lam g

(-1,2 trieu, -1,2 trieu)


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Van e la cho moi e doa b kien la khong ang s (incredible threat), v ben chovay tha mat tien con hn i kien (khong co li g hn cho ho).

Nh vay, chung ta se khong the dung can bang Nash n gian ma ket luan c g veviec ben cho vay co nh ng tien hay khong, neu khong tra li c cau hoi ho selam g neu ben vay khong tra n. e giai quyet van e can s dung mot cong cu khac- o la au tr th cap hoan chnh(subgame perfection). au tr th cap la cuoc au trtiep theo au tr lan au (s cap). Th du trong au tr gia ngi vay va ngi chovay, au tr s cap giai quyet van e "co cho vay hay khong?" au tr th cap giaiquyet van e "co the kien neu ben vay khong tra n khong?" Mot iem can bangNash ch hoan chnh neu no la chien lc an toan nhat trong moi cuoc au tr th cap.Mot cuoc au tr th cap phai thoa man ba ieu kien:

1) No bat au t ngon cua mot cuoc au tr s cap.2) No bao gom va ch bao gom cac phng an tiep theo chnh no (tc la

ch co quan he doc theo hng i xuong ma khong co quan he ngang).3) Khi xem xet chien lc toi u cho cuoc au tr th cap, can phai xemchien lc o co toi u cho tat ca cac cuoc au tr phia tren hay khong.

Khi xem xet ca ba ieu kien nay, cuoc au tr gia ben vay va ben cho vay ch conmot iem can bang Nash: khong cho vay. Khai niem au tr th cap cho ta thay ladung phap luat giai quyet bat c van e g cung phai co nhng giai phap toan dien,tong the, khong the ch ap dung nhng giai phap "can bang Nash" na vi. Th du ethu hut au t nc ngoai vao Viet nam, th ban than viec giai quyet nhanh chong thutuc cap giay phep au t hay mien giam thue cho nha au t la cha u. Xin phep

au t nhanh cung khong co ch g neu thu tuc trien khai cac d an au t cham, haychi ph kien tung oi n qua cao khi nha au t muon rut tien vay cho mot oi tactrong nc. Tng t, giai phap thu hut khach du lch vao Viet nam khong ch la tochc cac chng trnh le hoi dan toc hay am thc, khach san. No bao gom rat nhieukhau nh giai quyet thu tuc visa, m them ng bay en cac nc, van e ve sinhphong dch, au t cai tao moi trng ve sinh thanh pho, van e an toan cho du khach.Khi giai quyet cac van e thuoc ve au tr th cap, chung ta can xem xet: e at chieu qua mong muon th can phai ap ng nhng yeu cau g cho ngi chi? Chuyeng se xay ra tiep theo, va sau o chuyen g se xay ra tiep theo na?

Cuoc au tr cho vay-kien tung cho thay trong kinh doanh cac ben thng rat trongch tn, va neu hang hoa co loi th ngi ban co trach nhiem phai thay hang hoa mingay, con hn la i en luc b kien va phai chu nhieu chi ph hn. Chnh v the mangi mua thng thch mua hang co bao hanh hn hang khong co bao hanh. Tuynhien ch tn khong thoi cha u, v neu khong co s bao am la phap luat se cthc thi nhanhh chong va t ton kem th li ha ve ch tn cua cac ben khong u e trthanh cac cam ket ang tin cay. Ch khi o th viec kinh doanh gia oi ben mi tr


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thanh can bang Nash hoan chnh. Noi cach khac, e giai quyet bai toan ve au tr scap, can nam c luat chi cac cuoc au tr s cap. Muon bien can bang Nash scap thanh can bang Nash hoan chnh, phap luat phai ong vai tro la ong c khuyenkhch cac ben tien hanh nhng chien lc toi u cho au tr th cap trung lap vichien lc toi u cho au tr s cap.

Ket luan

au chng, chung ta co nhac en viec cac ben tien hanh au tr vi nhau khongch mot lan ma nhieu lan, trong mot thi gian dai. e nam c thong tin ve chienlc cua oi phng va xay dng chien lc cho mnh co hai cach. Mot la quan satxem ngi chi au tien a tien hanh chien lc g va co oi phap tng ng, datren viec xem xet tat ca cac kha nang xay ra (s o hnh cay) va lam phng phap quinap ngc. Phng phap th hai la phan tch cac chien lc toi u cuoc au tr s

cap va cac cuoc au tr th cap, va tm chien lc nao an toan nhat va co li nhat chotat ca cac cuoc au tr cua cac ben. Chien lc nay c goi la iem can bang Nashhoan chnh.

Vai tro cua phap luat la lam sao cho iem can bang Nash hoan chnh hay ket qua tphng phap qui nap ngc ong nhat vi chien lc toi u cua cac ben khi ho muoncong tac vi nhau. Muc ch la lam cho cac ben chuyen cach chi t cho ch lo enli ch ngan han en cho c khch le e theo uoi cac muc ch dai han va co licho xa hoi.

Mot trong nhng phng phap tac ong cua phap luat la thong qua khai niem cam kethay e doa ang tin (credible threat). Co ngha la, nhng g ma phap luat tuyen bo sekhuyen khch phai tr thanh hien thc, va nhng li e doa ap dung che tai phai cthc hien. Muon nh vay, phap luat ch nen khch le hay ngan can nhng g "kha thi."Th du Thong t cua Bo Van hoa Thong tin qui nh tat ca cac tin tc a len websiteeu phai c ang ky tai Bo, hay trc kia co quy nh ai mua au videocassettephai xin phep Bo Van hoa Thong tin. Cac quy nh nay khong nhng khong kha thi,ma con lam giam tnh nghiem tuc cua phap luat, v neu c quan hanh phap khong cokha nang thc thi nhng g mnh e ra th se lam cho cong chung mat niem tin vaohau qua phap ly. o cung la bai hoc au tien cua Ton t trong Binh phap: quan phap

phai c thc thi nghiem chnh.


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Chng 3: Tiet lo thong tin, yeu cau cong bo va thaoluan lai

Trong Chng 1, chung ta xem xet cac cuoc au tr trong o ngi chi co thong tinay u va tuyet oi (complete and perfect information). Trong Chng 2 chung taxem xet cac cuoc au tr trong o thong tin ay u nhng khong tuyet oi (completebut imperfect information - Chng 2) - co ngha la so lng thong tin ma moi benbiet ve nhau la nh nhau, vi ieu kien la mot ben i trc. Trong chng nay chungta xem xet van e thong tin khong ay u(ngha la mot ben biet ve nhng thong tinma ben kia khong biet). S bat oi xng ve thong tin nay (asymmetric information)se tao c hoi cho ben nam thong tin li dungben khong nam thong tin (moral hazard).Co rat nhieu th du ve thong tin khong ay u. Th du: ngi mua bao hiem biet nhieu

thong tin ve rui ro ma mnh xin mua (sc khoe, xe co) hn cong ty bao hiem, ngimoi nha biet nhieu thong tin ve nha at hn ngi mua nha, cong ty thu mua nong sanbiet nhieu thong tin ve gia ca th trng the gii hn ba con nong dan v.v.

Khi mot ben biet nhieu hn ben kia, se nay sinh van e: lam the nao e ben biet tthong tin nam c thong tin t phia ben kia. Tat nhien phng phap n gian nhat lanoi chuyenvi ben kia (cheap talk) , nhng lam sao co the kiem chng c thong tinma ngi kia cung cap? Cac phng phap e co the kiem chng thong tin hay thaoluan lai khi cac thong tin c kiem chng cho thay s that khong giong nh nhng gma ben kia a noi se c e cap trong Chng nay.

T tng ch ao hanh ong

Gia s trong mot cuoc au tr m rong, mot ben nam nhng thong tin ma ben kiakhong nam. e tm c thong tin t phia ben kia, mot trong nhng phng phap latm iem can bang hoan chnh Bayes (perfect Bayesian equilibrium). Ve ban chat,ay la phng phap loai suy e tm ra chien lc toi u cua oi phng, da tren motsoniem tin co c s (belief). C s cua niem tin nay la hai nguyen tac. Th nhat,ngi chi co ly tr se thay oi niem tin cua mnh khong phai da tren nhng g benkia noi, ma nhng g ben kia lam. Th hai, ngi chi co ly tr se hanh ong da tren

niem tin cua mnh. Tai iem can bang, t tng va hanh ong phai nhat quan vinhau, va nhat quan vi hanh ong cua nhng ngi chi khac. Mot th du cu the lakhi giao ket hp ong, khong nhng tuyen bo y ch (hanh ong) phai nhat quan vi ych (niem tin), magia y ch cua cac ben cung phai thong nhat vi nhau.

Chng trc, chung ta a e cap en au tr th cap hoan chnh, theo o iem canbang Nash phai toi u moi cuoc au tr th cap. Tuy nhien the nao la toi u th con


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tuy niem tin cua cac ben. Neu mot ngi muon oi mot chiec but may lay 1 chiecxe hi th cuoc trao oi ay van goi la toi u, neu ngi co chiec xe hi thc s muonoi chiec xe lay chiec but may. Nh vay khac vi iem can bang hoan chnh Nash,iem can bang hoan chnh Bayes at c khi hanh vi cua cac ben toi u xet ve niemtin cua ngi chi. Neu mot cach giai quyet c a ra khong nhat quan vi nhngg ma cac ben tin tng, th cach giai quyet o c coi la ang ng. Phng phapnay thng c dung trong khoa hoc ieu tra hnh s e ket toi mot nghi pham, neuphat hien li khai va hanh vi cua nghi pham co nhieu mau thuan.

Mot th du ve s thieu nhat quan gia t tng va hanh ong la cau truyen cua bophim ai bang Malta. Nhan vat chnh trong bo phim la Gutman, ngi a bo 17 name tm kiem bc tng ai bang nam ngoc ma cac hiep sy Malta dang tang vua Tayban nha. Cuoi cung ong ta tm c bc tng tai Istanbul trong tay mot v tng Ngala Kemidov. Bc tng b sn en va co ve nh khong co gia tr g lam. Gutman tra

gia cho bc tng kha cao, nhng Kemidov khong ban. Sau cung Gutman thue chai chuyen gia en anh cap bc tng, nhng hoa ra bc tng ch la ban sao cuabc tng that a c Kemidov cat dau.

Tat nhien Gutman khong noi vi Kemidov ve gia tr cua bc tng, nhng Kemidova oan ra c rang bc tng rat co gia tr qua cach mac ca de dai cua Gutman. Thdu Kemidov nh gia bc tng ch ang 10 USD, tuy nhien Gutman lai tra gia ti100.000 USD. Ban au chien lc toi u cua Kemidov la ban bc tng vi gia hn10 USD va cung lam la 100 USD, v ieu o phu hp vi niem tin cua ong. Tuynhien khi nghe Gutman chao gia cao hn mnh tng, Kemidov buoc phai ieu chnh

lai niem tin cua mnh - khong nhng bc tng ang gia hn 10 USD, ma tham ch noco the ang gia hn 100.000 USD. Xet cho cung, Kemidov khong anh gia thap oithu: Gutman khong phai la ke kh khao, va at han phai anh gia bc tng hn100.000 USD. Le ra Gutman a co the mua c bc tng vi gia 20 USD hay 100USD, nhng do ong a khong nam c niem tin cua Kemidov ve gia tr bc tngnen a mat c hoi mua lai.

Trong thc te kinh doanh cung co nhieu chuyen nh vay a xay ra. Khi nha may botgiat Viso lien doanh vi cong ty Unilever e thanh lap cong ty lien doanh Lever Viso,quyen s dung nhan hieu Viso c chuyen giao mien ph cho Unilever. Viso tin

rang gia tr tai san chu yeu cua mnh la nha xng va quyen s dung at ch khongphai nhan hieu. Tuy nhien khi Unilever lien doanh vi nha may P/S e thanh lap congty lien doanh Elida P/S th nhan hieu P/S c Unilever tra gia en 5 trieu USD, trongkhi toan bo nha xng va quyen s dung at ch c nh gia cha en 1 trieu USD.Khac vi Kemidov, P/S tuy thay Unilever tra gia cho nhan hieu cao hn mnh tngnhieu, song van khong ngh la gia tr thc cua P/S co the con cao hn na, va a ongy ban. Trong khi o Unilever a tnh: e chiem c 70% th phan Viet nam nh P/S


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Th du ngi ban sa bot phai quyet nh xem mnh nen ban cho nha san xuat so co lahay gi sa bot lai, loc va che thanh sa hop. Neu sa cua mnh b moc, ho se phaichu boi thng thiet hai cho nha san xuat so co la. Neu ngi ban sa quyet nh gisa lai e san xuat, ho se co li nhuan la 3USD trong khi nha san xuat so co la khongnhan c ong nao t quyet nh nay (v ho khong mua c sa). Neu ngi bansa quyet nh ban sa va th trc khi ban, ho phai th chat lng trc cho ngimua. Neu ho bo nhieu chi ph e th th se ch thu c li nhuan la 1USD. Neungi ban sa ch th s qua th co the at li nhuan en 5USD. Tuy nhien neu comot kien hang b moc va b khach hang kien th ho se khong con li nhuan. Nha sanxuat so co la cung phai th sa e e phong b khach hang kien. Neu ho th ky th chthu c 1USD li nhuan. Neu th s qua th co the thu c 3 USD li nhuan, nhngneu b khach hang kien th khong thu c ong nao. Ket qua (ngi ban, ngi muasa) c the hien theo s o sau:

Trong cuoc au tr nay ngi mua biet ngi ban a th sa nh the nao, va oi sachcua ca hai ben se dan en 2 iem can bang Nash. Mot la ngi ban th can than vangi mua th s qua. Hai la ngi ban th s qua va ngi mua th can than. Ngiban chac chan se th s qua, v tin rang ngi mua tha th lai cho chac (li nhuanbang 1) con hn la b khach hang kien va nhan li nhuan bang 0. Nh vay ngi bana li dung ngi mua (moral hazard). Cach suy luan cua ngi ban da tren phngphap qui nap ngc, bi le ngi mua biet ngi ban a th sa nh the nao khi nhansa, va buoc phai th ky khi biet ngi ban cha th ky. Trong cuoc song, cuoc autr nay xuat hien khap ni: gia th may va chu xng, gia nong dan va ngi thu

mua, gia nha cung cap nguyen vat lieu va ngi ban san pham cuoi cung cho ngitieu dung, xuat khau gao chat lng cao/thap, xuat khau hang hoa sang Hoa ky thongqua ai ly trung gian v.v.

Tuy nhien neu ngi mua cho ngi ban biet rang mnh se khong kiem tra mat hangky, ngi ban se phai th ky trc khi ban (v kha nang b khach hang kien). Nh vayngi ban tha gi sa lai (li nhuan = 3 USD) con hn ban sa (li nhuan = 1 USD).

Ngi ban sa gi lai

(1, 1)

Bat can

Ngi mua sa

Ban - th can than Ban - th s qua

Can thanBat can

Can than

(1. 3) (5, 1) (0, 0)

(3, 0)

Ngi mua sa


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Thong tin c kiem chng, t nguyen cung cap thong tin va manh moi

iem can bang hoan chnh Bayes va cac phng phap ieu chnh co the c s dungnh cong cu e cac ben tm thong tin thong qua hanh vi cua oi tac. muc nay chung

ta se xem xet vai tro cua ly thuyet xac suat oi vi quy nh trong hp ong mua banla ngi ban phai thong bao trc cho ngi mua ve nhng khuyet tat cua vat mua(goi la luat cung cap thong tin). Co hai loai thong tin. Loai th nhat la thong tin kiemchng c (verifiable) - th du kiem tra xem 1 chiec xe co chay tot khong, phanh coan khong. Loai thong tin th hai la thong tin khong kiem chng c (non-verifiable).Th du ngi chu muon kiem chng xem ngi gac cong co can than khong co thecan c vao viec anh ta co bat c trom khong. Tuy nhien ay cung khong phai la cs e tin cay. Mot ngi gac cong li bieng cung co the bat c trom, hay mot tentrom tai gioi co the tron thoat khoi ngi gac cong can than nhat.

Nh vay neu phap luat quy nh cac ben phai cung cap thong tin th khong the yeucau cung cap cac thong tin khong the kiem chng c. Th du anh Hai b ket toi"khong to giac toi pham" ch v khi anh nghe ban anh noi anh Nam lam tien gia makhong i bao canh sat. Li ket toi nay la vo ly, v anh Hai khong the kiem chngviec anh Nam co lam tien gia that khong. Cho du anh Nam co lam tien gia that thanh Hai cung khong co ngha vu phai kiem chng thong tin ma mnh nghe c. eket toi anh Hai, toa an phai da vao nhng chng c khac chng to anh Hai biet cnhng thong tin a c kiem chng, nhng khong i bao canh sat ngay.4

Trong cac loai thong tin kiem chng c, ngi ta thng quan tam en mot loai goi

la au moi(unravelling result). Th du trong mot hop tao boc kn co the cha en 100qua tao. Ngi ban biet so tao trong hop. Ngi mua khong the biet c so tao trkhi mua ca hop va ve nha m ra. Neu ngi ban noi rang trong hop co 100 qua tao,va sau o ngi mua ve nha ch em c co 90 qua, ngi mua co the kien ngiban. Tuy nhien neu ngi ban im lang khong noi g, th ngi mua khong the kienngi ban, v khong co au moi e khi kien.

Thong thng ngi ban se noi that cho ngi mua biet trong hop co bao nhieu quatao, v neu khong noi th khong lam cach nao thuyet phuc ngi mua mua tao c,va thong tin nay co the c kiem chng va lam ngi mua tin ngay. Gia s bay gingi ban co 99 qua tao va quyet nh khong noi g vi ngi mua ve so tao. Viecngi ban im lang se lam ngi mua nghi la trong hop khong co ti 100 qua tao, nhvay ngi ban 99 qua tao cung khong hn g ngi ban 70 qua tao trong cung 1 hop.Ket qua la ngi ban se noi that vi ngi mua ve so tao mnh co trong hop. Cac ket

4Cau chuyen nay da tren mot vu an co that xay ra Tp. Ho Ch Minh nam 2000.


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qua nh vay goi la "au moi" hay thong tin co e lai dau vet ( unravelling result) ephan biet/kiem chng ngi mua ban trung thc va ngi mua ban gian doi.

Trong luat hnh s cung co cac quy nh phan biet gia cac thong tin "au moi" va cacthong tin khong phai au moi. Th du BLTTHS quy nh li khai cua ngi lamchng co the khong c cong nhan neu trong qua kh ngi nay a tng gian doitrc toa hay cac c quan nha nc. Tng t luat cung quy nh ngi nao co moiquan he vi ng s th khong c tham gia c quan tien hanh to tung. Nhngngi co moi quan he nhng khong chu khai bao, khi phat hien se tr thanh nhngngi khong ang tin cay. V thong tin co quan he hay khong la thong tin co the kiemchng c (e lai dau vet), nen tot nhat la nhng ngi co moi quan he nen t khaive moi quan he cua mnh va rut lui khoi danh sach c quan tien hanh to tung. Mot thdu na la BLHS quy nh toi khong to giac ngi pham toi khong ap dung oi vi chame, v chong hay con ngi pham toi. Neu khong co ieu khoan nay, khi c quan

ieu tra hoi cung than nhan ngi pham toi va ho im lang, th c quan ieu tra co thecoi ay la au moi e ket luan la ngi b hoi cung "ang co ieu g muon dau diem,"tng t nh ngi ban tao trong cau chuyen ke tren.

My con co quy nh cam cac ngan hang cong bo cac bien ban kiem tra tai chnhcua mnh. Ly do la v neu mot ngan hang co 1 so khuyet iem va khong chu cong bobien ban kiem tra se b khach hang coi la "co van e" va xep cung loai vi nhngngan hang kem. Trong khi o neu ngan hang co bien ban tot, ho se t nguyen congbo, khien khach hang tin rang cac ngan hang khong cong bo la ngan hang kem. ieunay se khien nhng ngan hang v tr trung bnh bat li.

Trong luat dan s hay lao ong, cac quy nh ve ngha vu chng minh c phan chiasao cho ngi nam thong tin phai chng minh nhieu nhat. Th du neu ngi s dunglao ong muon sa thai ngi lao ong v ly do kho khan kinh te, th ngha vu chngminh cac kho khan nay thuoc ve ngi s dung lao ong. Ngc lai, khi mot ngi togiac ngi khac xam pham quyen s hu tr tue, ho co quyen yeu cau ngi b to giaccung cap cac thong tin can thiet ve hanh vi pham toi. Ly do la v ngi pham toi langi biet ve hanh vi cua mnh hn nan nhan, va xam pham quyen s hu tr tue khophat hien hn nhng hanh vi xam pham khac.

Luat yeu cau cong bo thong tin va nhng han che cua luat

Quy tac "au moi" thong tin co s dung c hay khong phu thuoc vao kha nang motngi chi tm c thong tin t s im lang cua ngi kia. Tuy nhien neu ngi imlang thc s khong biet g ve thong tin ma ngi chi can biet th quy tac au moikhong ap dung c . Nh vay luat yeu cau cong bo thong tin phai phan biet cgia ngi nam thong tin va ngi khong nam thong tin g. Th du luat bao hiem yeu


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cau ngi mua bao hiem phai cung cap ay u thong tin ve rui ro cho ben nhan baohiem, hay quy nh ve hp ong mua ban yeu cau ngi ban phai thong bao chongi mua ve nhng khuyet tat.

Tuy nhien luat cung quy nh ngi ban khong chu trach nhiem ve viec khong thongbao nhng khuyet tat khi ban o cu, neu mnh khong biet hay khong the biet vao thiiem ban vat. Gia s mot ngi mua nha en hoi ngi ban xem can nha mua cobmoi xong hay khong. Ngi ban tra li "theo nh ong ta biet" th can nha khong bmoi xong. Neu sau o ngi mua phat hien can nha o qua thc b moi xong, th ongta cung khong the kien ngi ban oi boi thng, neu khong chng minh c rangqua thc ngi ban biet can nha b moi xong.

Mot th du tng t ve han che cua quy tac au moi la khi au t mua lai mot nhamay, hay khi cho mot cong ty vay tien, chu au t hay chu n thng yeu cau mot

luat s viet tra li 1 so cau hoi. Cac cau hoi nay co the bao gom: ngi i vay co phaila mot cong ty c thanh lap hp phap theo luat Viet nam hay khong, hay hp ongsoan thao co c phap luat Viet nam cong nhan hay khong. Tuy nhien luat s khongthe tra li c nhng cau hoi ma ban than ho khong biet - th du ngi i vay co b aikien tung bao gi cha hay ho co phai la ngi ang tin cay hay khong. oi hoi luat s tra li nhng cau hoi nh vay la vo ly. Trc kia chung ta cung co quy nh latai san the chap phai c cong chng vien nh gia. Trong vu an EPCO-MinhPhung, mot so tai san the chap a c nh gia thong qua cong chng vien cao hnhang tram lan e mang i the chap va cho vay. Tat nhien mot vai cong chng vienthoai hoa bien chat a tao ieu kien e that thoat tien cua Nha nc, tuy nhien luat

phap quy nh cong chng vien phai chu trach nhiem ve gia tr tai san the chap la voly. Muon chu trach nhiem cong chng vien phai nam c thong tin va kiem chngc thong tin, trong khi cong chng vien lai khong co kha nang nay va khong thelam au moi thong tin cho ngan hang. Hn na gia tr tai san la do th trng quyetnh, gia hom nay khong phai la gia ngay mai. Mot hp ong cho vay 10 nam ma chda vao gia tr tai san tnh mot thi iem nhat nh la da tren nhng thong tinkhong chnh xac va khong c kiem chng bi thi gian.

Quy tac au moi thong tin cung ch ap dung c trong trng hp mot so gia thiet laung. Th du trong trng hp mua tao, th chung ta gia thiet la ngi mua thch nhieu

tao hn t tao. Trong trng hp mua 1 hop so co la, ngi mua quan tam en mausac, mui v, chat lng cua cac vien so co la hn so lng cua chung. V moi ngimua co mot khau v khac nhau, nen ngi ban cung khong biet the nao machieu longngi mua, v vay ho co the chon mot trong hai giai phap. Mot la im lang. Co nghala ngi mua cung khong the kien ngi ban, va toa an cung khong the biet ngiban im lang la v biet ma khong noi hay thc s khong biet. Giai phap th hai la hoixem ngi mua muon g va tra li thanh thc xem san pham cua mnh co phu hp vi


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muon nhan 186,67 cay vang th khi a co thong tin se muon nhan theo xac suat trungbnh la 186,67 + 6,67 = 193,33 cay vang. Neu chi ph kiem tra vt qua 6,67 cayvang, va khi kiem tra xong co the b mat (200 - 186,67) = 13,33 cay vang (v ngimua ch tra 186,67 cay neu ngi ban im lang) th tat ca ngi ban co the tnh enchuyen khong kiem tra na. Luc nay ngi mua lai phai ieu chnh niem tin cuamnh. V biet ngi ban khong kiem tra, va xac suat gia nha tot va nha xau la p' =1/2, ho se tra EPV = p' x 200 + (1-p') x 180 = 190 cay vang. Khi ngi mua tra ch co190 cay vang, co ngha la thong tin ve can nha tot tr gia 200 - 190 = 10 cay vang.Kha nang (xac suat) kiem c 10 cay vang nay nh kiem tra la 1/2 (50% sau khikiem tra la nha tot va 50% sau khi kiem tra la nha xau). Nh vay ngi ban ch botien ra kiem tra nha neu chi ph kiem tra khong vt qua 10 x 50% = 5 cay vang. Gias chi ph kiem tra can nha ton khong en 5 cay vang, nh vay tat ca ngi ban sekiem tra va tr thanh "au moi thong tin." Luc nay ngi mua se phai ieu chnh lainiem tin cua mnh, va khong tra gia 190 cay vang cho ngi mua im lang na ma ch

tra 180 cay vang (v ngi ban biet ve tnh trang can nha ma im lang co ngha la nhacan sa).

Trong thc te t khi kiem tra 1 can nha ton en 5 cay vang, nhng chung ta th giathiet 1 trng hp khac: ngi ban suy tnh xem co nen sn va sa lai can nha mnhnh ban hay khong. Tien sa lai het 10 cay vang. Neu sa ton 10 cay ma ban ikhong hn c 10 cay so vi luc cha sa th ro rang la ngi ban khong nen sa.Trong thc te kinh doanh cung vay. e thu hut nha au t vao 1 khu cong nghiep,ban quan ly thng co chnh sach la giam hay mien tien thue at. Tuy nhien oi vinha au t th tien thue at ch la mot mat, va neu ho muon au t th du gia thue at

co cao ho van au t, neu khong thay au t la co li th du gia thue at co thap hocung khong au t. Nh vay viec mien giam tien thue at cung khong lam tang cacd an au t len c la bao. o la tnh trang chung cua au t nc ngoai vao Vietnam trong 5 nam qua.

Noi tom lai oi vi phng an th nhat, van e au tr gia ngi ban nha va ngimua nha, hay gia ban quan ly khu cong nghiep va nha au t, la chi ph mamotben phai bo ra e ap ng nhng nhu cau cua ben kia va ong thi van co li chomnh.

Bay gi chung ta xet en phng an th hai (phap luat qui nh ngi ban bat buocphai nam thong tin va thong bao cho ngi mua). Neu chi ph e nam thong tin quacao, ngi ban se buoc phai tnh chi ph nay vao gia can nha. Nh vay gia mot cannha tot khong phai la 200 cay ma la 210 cay (gia thiet chi ph kiem tra nha het 10cay), gia 1 can nha xau se la 190 cay. Ngi mua luc nay se b thiet hai, v neu biettrc la 1 can nha xau ma van phai tra 190 cay th chang tha khong biet g ve tnh


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trang can nha va tra 186,67 cay (nh trong phng an th nhat) con hn. Nh vayphng an th hai cung khong phai la phng an toi u.

Bay gi chung ta xet en phng an th 3 (ngi ban khong bat buoc phai nam thongtin, nhng neu nam thong tin th phai thong bao cho ngi mua). Phng an nay degiai quyet hn ca. Ngi ban nam thong tin co xac suat nhan c 200 cay va 180 cayla nh nhau (50%). Tuy nhien ho phai tr i chi ph e nam c thong tin. Neu hokhong nam thong tin va im lang, ngi mua se hieu la ho khong biet, va v the chochac an se tra gia la 190 cay (trung bnh cong gia tr chenh lech gia nha tot va nhaxau). Ngi ban coi thong tin mnh nam c tr gia 10 cay (neu la thong tin "nhakhong can sa") va -10 cay (neu la thong tin "nha can sa"). V xac suat nhan cthong tin theo hai hng la nh nhau, nen xet ve lau dai (neu ngi ban co nhieu cannha e ban) th thu thap thong tin se khong lam cho ngi ban thu li nhieu hn lakhong thu thap. Nh vay thong tin ve can nha cung khong co gia tr g, va ngi ban

se khong thu thap thong tin, cho du chi ph thu thap thong tin co thap i chang na.Th du chi ph thu thap thong tin ch het 1 cay, nhng neu o la thong tin bat li th selam cho ngi ban mat 10 + 1 = 11 cay so vi khi khong co thong tin (190 cay so vi(180 - 1) cay). V xac suat nhan c thong tin theo hai hng la nh nhau nen thuthap hay khong cung khong lam thay oi gia tr trung bnh cua can nha la 190 cay.Van e quyet nh thu thap thong tin hay khong ch thay oi khi xac suat nha khongcan sa ln hn nha can sa.

Thong qua 3 phng an, chung ta thay phap luat ong vai tro quan trong trong viecphan phoi cac chi ph e thu thap thong tin va cho ra nhng ket qua khac nhau. Khi

phap luat khong can thiep (phng an 1), cac ben trong cuoc au tr se trong trangthai "tu mu" va phai s dung iem can bang Bayes va ly thuyet xac suat e giai quyetvan e. Khi phap luat can thiep theo hng cac ben khong can nam tat ca cac thongtin, nhng phai cong bo nhng thong tin ma mnh biet, th moi hanh vi cua ngi ban(cong bo thong tin hay im lang) se c ngi mua hieu ro hn. Luc o tnh trang"thong tin bat oi xng" se khong con va cuoc au tr cua cac ben se c qui ve cacdang thong tin hoan chnh va ay u nh a e cap Chng 1 va 2. Tom lai, cacquy nh ve buoc cong bo thong tin co the giup cho cac ben lap c chien lc toi ucho mnh, vi ieu kien la thong tin c cong bo phai co gia tr va kiem chng c.

e biet gia tr thc cua thong tin can nam vng cac qui tac xac suat e tnh gia tr cuathong tin trong mot thi gian dai. Cac th du cung cho ta thay tuy thong tin la quantrong, nhng xet ve lau dai cha chac nam c thong tin a hn g khong nam cthong tin, neu xac suat ve ket qua tot hay xau cua thong tin la nh nhau. Chnh v vayma ngi ta khong i mua ve so (may t hn rui nhieu) hay i xem boi (t le ung saicua thay boi la 50/50).


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co gang cua ben nay co the c ben kia quan sat, song cha chac g a c ben kiakiem chng va cong nhan. Gia s ben no lc la ben ban, ho se cam thay no lc cuamnh khong c ben mua cong nhan, va khong cam thay c khuyen khche tieptuc au t cho san pham.

e tao c c che khuyen khch, can thiet ke mot khung phap ly sao cho ngi muahang co the khuyen khch ngi ban hang au t va ngc lai. Neu hp ong ch baogom gia va so lng (ma khong noi en chat lng), ngi ban se khong cam thayphai no lc cai tien chat lng. V ngi mua thay chat lng nguyen vat lieu khongcai tien, ho cung khong au t e phat trien cac san pham da tren nguyen lieu nay,va cung khong tra gia cao cho nguyen vat lieu. Quan he gia hai ngi ri vao vongluan quan: chat lng kem - gia thap - khong au t - chat lng kem va c the tieptuc.

Cac ben cung co the ky mot hp ong dang m: gia co nh, song so lng thay oi.Ngi mua co the chon mua 1 tan hay khong mua ma khong phai boi thng. V giaca co nh nen ngi mua cung khong cam thay c khuyen khch, va v the lai rivao vong luan quan chat lng kem - gia thap - khong au t. Khi ngi ban akhong co c che e nang cao chat lng, viec ngi mua co e doa khong mua cungkhong lam cho chat lng san pham tang len (gia s ngi ban co the ban san phamcua mnh cho ngi khac).

Gia s hp ong c at m vi gia co nh cao hn gia th trng. Luc nay viec benmua e doa se khong mua se lam ben ban s (credible threat - xem chng 2) va phai

au t e tang chat lng. Tuy nhien ngi ban cung ch tang chat lng cho en khigia sa bang vi chi ph bien te e san xuat ra so sa o. Cao hn na th ngi bankhong the tiep tuc chu lo. Trong thc te, cac nhan vien lam cho cac tap oan aquoc gia tai Viet nam thng c tra lng cao hn nhieu so vi mc lng trungbnh tren th trng. Muc ch cua viec tra lng cao la e ngi lao ong s b matviec va v the phai tang nang suat va lam viec cham ch hn. oi vi cong ty, ho thatra lng cao cho mot ngi ang lam viec hn tra lng thap cho mot ngi chuyent cong ty khac sang, v ho can co thi gian e tm hieu xem ngi mi co thc s lamviec hieu qua hn ngi cu hay khong.

Ngc lai, yeu cau tang chat lng cua ben mua lai khong co gii han. Chat lngnguyen vat lieu cang cao,ho cang muon au t vao day chuyen san xuat v san phamtao ra t chat lng cao de ban hn. Lam the nao e thiet lap mot c che khuyenkhch ngi ban va co li cho ngi mua, trong khi ngi ban muon ban at va ngimua muon mua re?


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e giai quyet van e nay can tr lai cong thc E(v) = v + k s + kb va xac nh mot cche gia linh ong. Theo o tien li cua ngi mua t viec ban san pham se c tralai 1 phan cho ngi ban theo t le c nh san ve gia nguyen vat lieu. Bang cacho, hp ong c thng thao lai lien tuc khi hoan canh (li nhuan cua ben mua)thay oi. Nh vay viec tao ra c che thao luan lai trong mot hp ong dai han quantrong hn.

Ngoai cac ieu khoan ve thao luan lai, ieu khoan ve cham dt hp ong cung quantrong, cho du o khong phai la ieu ma cac ben mong muon. Nguyen nhan la v oivi nhng cuoc au tr dai han, mot trong nhng phng phap e at c can banggia cac ben la i ra ngoai pham vi can bang (off the equilibrium path - xem chng2). Xu hng nay neu la s e doa ang s (credible threat) va se lam cho oi tacphai thay oi chien lc theo hng can bang. Neu cham dt hp ong la s e doakhong ang s th no se khong c s dung, ma cac ben se ngh en thao luan lai

hp ong hn.Han che kha nang thao luan lai

Mac du thao luan lai co mot so u iem, no ch phat huy u iem neu xay ra ungthi iem va tao c the can bang co li cho xa hoi. Neu ieu nay khong xay ra,cac ben co the muon han che kha nang thao luan lai hp ong.

Gia s UBND thanh pho quyet nh m rong ng Cach mang Thang 8 vi chi phhang ty USD va to chc au thau. Neu cong ty trung thau ma c nhan 1 khoan tien

co nh e xay dng con ng, trong khi o nha nc khong biet kiem chng chatlng cong trnh nh the nao, co the xay ra cac trng hp lam dung. Th du cong tyxay dng an bt vat lieu hay cham tre trong xay dng. Nh vay UBND thanh pho cothe cho phep cac ben thao luan lai ieu kien hp ong neu chat lng cong trnhkhong bao am. ieu nay tat nhien cung co li cho cong ty xay dng, v no co nghala khi gia thanh nguyen vat lieu tang qua nhanh, ho cung co the yeu cau UBND thaoluan lai hp ong.

Xet be ngoai th ieu khoan thao luan lai co ve la co li cho ca hai ben. Tuy nhienneu nhn vao thc te th ieu nay bat li cho UBND hn la co li. Cong ty trung thau

co the y lai vao kha nang thao luan lai hp ong ma khong co gang, Ke ca neu congtrnh khong at yeu cau, UBND cung khong the cham dt thau va thue ngi khac, vnh vay chi ph se con ln hn. Trong trng hp nay UBND van phai thao luan laihp ong va cho phep cong ty tiep tuc xay dng va sa lai cong trnh. S co ham chuiVan thanh la mot th du ien hnh.


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mnh can. Phat tn hieu ngha la ngi co thong tin truyen thong tin cho ngi khacthong qua hanh vi cua mnh. Chon loc co ngha la ngi khong co thong tin chon cacchien lc sao cho ngi co thong tin t boc lo thong tin cua mnh.

Tron cac trng hp tren, phap luat khong the quy nh ngi li bieng phai noi chongi s dung lao ong biet la mnh li, v se khong ai noi nh vay ca. Tng t,ngi ban hang khong bao gi noi la hang cua mnh chat lng khong tot. Mot ngiban nc mam bao gi cung noi hang hoa cua mnh co hai loai: loai tot va loai haohang. Tuy nhien, neu khach hang yeu cau hang hoa phai co bao hanh th ch nhngngi co hang tot mi dam bao hanh hang hoa cua mnh. Trong trng hp nh vay,phap luat khong nen qui nh tat ca cac hang hoa c ban phai co bao hanh, v lamnh vay se dap tat tn hieu ma ngi ban hang tot muon phat cho khach hang (v aicung phat cung mot tn hieu nh nhau).

Ben canh bao hanh, quang cao cung laphng phap phat tn hieu. Ngi co hang totse quang cao manh e ngi mua hang biet hang mnh tot va lan sau quay lai mua.Ngi co hang khong tot neu quang cao manh se lam ngi mua mat long tin va lansau se khong mua hang na cho du chat lng co kha hn. Quang cao co li cho cangi mua lan ngi ban, song ngi ban thng co li nhieu hn. Mot khi ngimua nhan c tn hieu va kiem chng c thong tin quang cao, ho a co mot niemtin (xem chng 3). T o ngi mua se co chien lc hanh ong theo niem tin tr khichat lng hang hoa tr nen qua xau en mc ho phai anh gia lai niem tin cua mnh.Viec phat tn hieu co the the c mieu ta tot nhat qua th nghiem cua nha sinh vathoc Pavlov: ong cho cho an ong thi rung chuong. Sau nhieu lan rung, no tr thanh

tn hieu cho cho tiet nc bot (phan xa), tham ch khi rung chuong ma khong co thcan. Tuy nhien neu thc hien th nghiem nay qua nhieu lan ma khong cho cho an, nose thay oi niem tin va khong tiet nc bot na.

Trong phan tiep theo, chung ta se quan sat xem cac ben co the phat hay thu tn hieuqua cac cuoc au tr m rong nh the nao.

Mo hnh s dung thong tin khong kiem chng c

Viec xay dng mo hnh nham muc ch giup chung ta hieu c xu hnghanh ong

cua ngi chi, ch khong phai e oan chnh xac xem ngi chi se hanh ong nhthe nao. Th du khong ai ngh rang c he quang cao th doanh thu se tang len. Tuynhien thong thngngi ta mua hang v quang cao, neu nh hien tai ho cha bietnen mua mat hang g.

Qua cac chng trc, chung ta a xet cac cuoc au tr da tren cac mo hnh, theo omuon cac ket luan ung can phai co mot so gia thiet. Th du chung ta gia thiet ngi


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Tr lai cuoc au tr la chon ang vien. Sau khi ngi c hoi thay ch nhng ai chonlp yeu mi c c i ao tao, ho se chuyen sang chon lp yeu. Ngi thc longcung muon chon lp yeu e "phat tn hieu" cho to chc biet la mnh nhiet tnh. Khingi nao cung muon chon lp yeu th

Documents

LCT_Dau_tri_va_Luat.pdf