本科毕业外文资料翻译.docx

本科毕业外文资料翻译.docx

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本科毕业外文资料翻译

外文资料翻译—原文部分

BiddingClubs:

InstitutionalizedCollusioninAuctions

（FromKevinLeyton．BiddingClubs：

InstitutionalizedCollusioninAuctions，ACM[J]．

2000，（11）：

272—27）

Weintroduceaclassofmechanisms,calledbiddingclubs,foragentstocoordinatetheirbiddinginauctions.Inabiddingclubagentsfirstconducta“pre-auction”withintheclub;dependingontheoutcomeofthepre-auctionsomesubsetofthemembersoftheclubbidintheprimaryauctioninaprescribedway;and,insomecases,certainmonetarytransferstakeplaceaftertheauction.Biddingclubshaveself-enforcingcollusionpropertiesinthecontextofsecond-priceauctions.Weshowthatthisisstilltruewhenmultipleauctionstakeplaceforsubstitutablegoods,aswellasforcomplementarygoods.Wealsopresentabiddingclubprotocolforfirst-priceauctions.Finally,weshowcaseswherebiddingclubshaveself-enforcingcooperationprotocolsinarbitrarymechanisms.

WiththeexplodingpopularityofauctionsontheInter-netandelsewherehascomeincreasedinterestinsystemstoassist（softwareorhuman）agentsbiddinginsuchauctions.Mostofthesesystemshavetodatedonelittlemorethanaggregateinformationfrommultipleauctionsandpresentittotheuserinaconvenientfashion（e.g.,）.Thereisnowbeginningtoemergeasecondgenerationofsystemswhichactuallyprovidebiddingadviceandautomationservicestobidders,goingbeyondthefamiliarproxybiddingfeatureprevalentinonlineauctionstotherealmofbona-fidedecisionsupport.

Thispaperlooksevenbeyondsuchsystems,whicharegearedtowardsassistingasinglebidder,andpresentsaclassofsystemstoassistacollectionofbidders,“biddingclubs”.Theideaissimilartotheideabehind“buyerclubs”ontheInternet（e.g.,and）,namelytoaggregatethemarketpowerofindividualbidders.Thenewtwististhatwhereasinabuyerclubthereisaperfectalignmentofthevariousbuyers’interests（sincetherethemorebuyersjoininapurchasethelowerthepriceforeveryone）,inabiddingclubthereisamorecomplexstrategicrelationshipamongthem,andthebiddingclubrulesmustbedesignedaccordingly.

Here’sasimpleexample.Consideranauctionwithasingleseller,andsixpotentialbuyers.Assumethatthreeofthepotentialbuyers–A,BandC,withcorresponding（secret）valuationsv1>v2>v3–attempttocoordinatetheirbidding.Assumetheauctionisafirst-priceauction.Underwellknownassumptionsfromtheauctionliterature,itwouldbetheinterestofeachbiddertobidexactly5/6ofhistruevalueintheauction.ThusAwouldendupwithasurplusofv1/6（ifhewinstheauction）or0（ifhedoesn’t）,andBandCwithasurplusof0.Istheresomepre-agreementA,BandCcanmakethatwillcauseallofthemtocomeoutoftheauctionatleastaswelloff,andsomeofthemstrictlybetteroff?

Onecouldnaivelysaythattheywouldeachrevealtheirvaluationstooneanotheragreeingthatonlythehighestwouldgoontotheauction;Awouldthere-forebetheonegoingon,andwhenhebidsintheauctionhewouldbidlowerthan5v1/6（abidof3v1/4willwork,giventheabove-mentionedassumptions）,andthusincreasehisexpectedsurplus.TheobviousflawinthismechanismisthatA,BandCwillhaveincentivetolieinthisinitialphase;thiscouldstillbetrueifAwereobligedtopayBandCacertainamountiftheysatitoutandhewontheauction.

Theaboveprotocolisasimpleinstanceoftheclassbiddingclubs.Ingeneral,givensomeprimarymechanism（typically,anauction）,abiddingclubprotocolisasfollows:

1.Somesetofbiddersareinvitedtojointhebiddingclub,andinformedofitsrules.Theotherbiddersarenotmadeawareoftheexistenceofthebiddingclub;weassumeherethattheyarenotevenawareofthepossibilityofitsexistence.

2.Thebiddershavethefreedomtojointheclubornot.Iftheydoitisassumedthattheyareguaranteedtofollowitsrules.

3.Thebidding-clubcoordinator（orsimply‘coordinator’）asksthemembersforcertainprivateinformation,suchastheirvaluationsforthegoodthatisbeingsold.Noticethatingeneralbiddersmaycheatabouttheirvaluations.

4.Thecoordinatordetermines,accordingtopre-specifiedrules,howthemembersshouldbehaveintheprimarymechanismbasedontheinformationtheyallsupply.

5.Thecoordinatormayalsodetermine（andenforce）additionalmonetarytransfersoftheclubmembers,basedontheresultsofthemainmechanism.

6.Thecoordinatoractsonlyasarepresentativeofbidders.

Itmayseemnaturaltoaskwhyacoordinatorshouldbewillingand/orabletofunctionasatrustedthirdparty,withoutattentionhavingbeenpaidtoitsownincentives.Webelievethatitisbestnottoseethecoordinatorasaparty（withinterestsofitsown）atall;rather,weconceiveofacoordinatorasasoftwareagentwhichisabletoactonlyaccordingtoits（commonly-known）programming.Itisthereforepossibleforthecoordinatortoactreliably—andforagentstobeconfidentthatthecoordinatorwillactreliably—evenincaseswherethecoordinatorstandstogainnothingthroughitsefforts.Wedoassumethatcoordinatorsshouldnotcostmoneytooperate—allofourcoordinatorsarebudget-balancedexceptforonethat（unavoidably!

）makesmoney.Finally,wehaveoftenbeenaskedaboutthelegalissuessurroundingtheuseofbiddingclubs.Whilethisisaninterestingandpertinentquestion,itexceedsbothourexpertiseandthescopeofthispaper.

Itturnsoutthat,whilethesimplemechanismoutlinedearlierfails,amoresophisticatedonewillensurethatBandCdonotparticipateintheprimaryauction,andthatAisthereforeassuredhigherexpectedpayoffintheauction.Moregenerally,thecontributionsofthispaperareasfollows:

1.Wepresentaprotocolforself-enforcingcooperationinsecond-priceauctionsforsubstitutegoods.

2.Wepresentaprotocolforself-enforcingcooperationinsecond-priceauctionsforcomplementarygoods.

3.Wepresentaprotocolforself-enforcingcollusioninfirst-price（aswellasDutch）auctions,inwhichonlysomeoftheagentscoordinatetheiractivities,andwhichdoesnotmakeanyuseofmonetarytransfers.

4.Wepresentaprotocolforself-enforcingcooperationingeneralauctionsandeconomicmechanisms,whentheagents’types（e.g.valuationsforgoods）aretakenfromafiniteset.

Thestrategicinteractionamongself-interestedagentsisaprimarytopicofstudyinmicroeconomics[4]andgametheory[1].Inparticular,thedesignofprotocolsforstrategicinteractionsisthesubjectofthefieldtermedmechanismdesign[1].Theroleofamechanism（inparticular,auction）designeristodefineagamewhoseequilibriumstrategiesaredesirableinsomerespectoranother.Thus,thedesignofabiddingclubconsistsoftakingagivenmechanism–theprimaryauction–andturningitintoamoreelaborateone,namelyonewithanaddedfirststageinwhichasubsetoftheplayersplayinsomenewly-designedgame（aswellassomeadditionalrulesregardingbehaviorintheprimaryauctionandpossiblesidepaymentsaftertheauction）.

Researchonstrategicaspectsofmulti-agentactivityinArtificialIntelligencehasgrownrapidlyintherecentyears.Thisworkhasconcentratedonthedesignofprotocolsforagents’interaction[7,3,9],andsharesmuchincommonwithworkonmechanismdesignineconomics.Manyprinciplesandideasgrewupfromthemechanismdesignliterature,andhavebeenadaptedtotheAIcontext.

AlthoughthestudyofdealsamongagentshasreceivedmuchattentionintheAIliterature（seee.g.[7]）,andalthoughthestudyanddesignofcontractsiscentraltoinformationeconomics[4]（andreceivedmuchattentionintherecentAIliterature[8]）,theliteratureoncooperationunderincompleteinformationinauctionsandtradesisquitelimited.Inparticular,theliteratureoncollusioninauctionsissomewhatspotty.Itisstilltoobroadtogiveacompleteoverviewofit,andthebulkofitisinformal.Intheformalliteratureonthetopic,theresultsarequitespecific,andcertainlydonotapplyinsettingsofparallelauctions（witheithersubstitutabilityorcomplementarityamonggoods）,first-priceauctionswithoutside-payments,andgeneralmechanisms,whicharethefocusofourtechnicalresults.TheclosestresultfromtheliteratureofwhichweareawareisbyGrahamandMarshall[2],whopresentaprotocolforself-enforcingcollusionbyasubsetoftheparticipantsofa（single-good）second-priceauction.Wediscussthisresultbelow.Additionalrelatedstudyofcollusioninauctionscanbefoundin[5].

Wenowpresentsomepreliminariesofauctiontheory,aswellasadescriptionoftheclassicalauctionmodeldiscussedinthepaperandourparallelauctionmodel.

Inordertoanalyzeauctionswehavetodiscusstheinformationavailabletotheparticipants.Weassumetheindependentprivatevaluesmodel,withnoexternalities.Eachagentiisassumedtohaveavaluationviselectedfromtheintervalofrealnumbers[0;1]orfromafinitedomain,whichcapturesitsmaximalwillingnesstopayforthegood.Wefurtherassumethatthisvaluationisselectedfromtheuniformdistributionontheinterval[0;1]oronafinitedomain.Foreaseofpresentationwewillassumethecontinuouscase,excludingthesectionongeneralmechanisms,wheretheassumptionthatthesetofpossiblevaluationsisfiniteisrequiredforourresult.Ifagentiobtainsthegoodandisaskedtopayp,aswellasaparticipationfeed,thenitsutility,ui,isgivenbyvi.p.d;otherwise,ifitisnotassignedanygoodthenitsutilityis.d;iftheagentdoesnotparticipateintheauctionthenits