?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.title=Allocative+and+informational+externalities+in+auctions+and+related+mechanisms&rft.creator=Jehiel%2C+P.&rft.creator=Moldovanu%2C+B.&rft.description=We+study+the+effects+of+allocative+and+informational+externalities+in+(multi-object)+auctions+and+related+mechanisms.+Such+externalities+naturally+arise+in%0D%0Amodels+that+embed+auctions+in+larger+economic+contexts.+In+particular%2C+they+appear+when+there+is+downstream+interaction+among+bidders+after+the+auction%0D%0Ahas+closed.+The+endogeneity+of+valuations+is+the+main+driving+force+behind+many+new%2C+specific+phenomena+with+allocative+externalities%3A+even+in+complete+information+settings%2C+traditional+auction+formats+need+not+be+efficient%2C+and+they+may+give+rise+to+multiple+equilibria+and+strategic+non-participation.+But%2C+in+the+absence+of+informational+externalities%2C+welfare+maximization+can+be%0D%0Aachieved+by+Vickrey-Clarke-Groves+mechanisms.+Welfare-maximizing+Bayes-Nash+implementation+is%2C+however%2C+impossible+in+multi-object+settings+with+informational+externalities%2C+unless+the+allocation+problem+is+separable+across+objects+(e.g.+there+are+no+allocative+externalities+nor+complementarities)+or+signals+are+one-dimensional.+Moreover%2C+implementation+of+any+choice+function%0D%0Avia+ex-post+equilibrium+is+generically+impossible+with+informational+externalities+and+multidimensional+types.&rft.publisher=ESRC+Centre+for+Economic+Learning+and+Social+Evolution&rft.date=2006-03&rft.type=Working+%2F+discussion+paper&rft.language=eng&rft.source=++++(ELSE+Working+Papers++185).+ESRC+Centre+for+Economic+Learning+and+Social+Evolution%3A+London%2C+UK.+(2006)+++++&rft.format=application%2Fpdf&rft.identifier=https%3A%2F%2Fdiscovery.ucl.ac.uk%2Fid%2Feprint%2F14538%2F1%2F14538.pdf&rft.identifier=https%3A%2F%2Fdiscovery.ucl.ac.uk%2Fid%2Feprint%2F14538%2F&rft.rights=open