false-name-proofness with bid withdrawal
We study a more powerful variant of false-name manipulation in Internet auctions: an agent can submit multiple false-name bids, but then, once the allocation and payments have been decided, withdraw some of her false-name identities (have some of her false-name identities refuse to pay). While these withdrawn identities will not obtain the items they won, their initial presence may have been beneficia to the agent's other identities. We defin a mechanism to be false-name-proof with withdrawal (FNPW) if the aforementioned manipulation is never beneficial FNPW is a stronger condition than false-name-proofness (FNP). We discuss the relation between FNP and FNPW in general combinatorial auction settings. We also propose the maximum marginal value item pricing (MMVIP) mechanism, which we prove is FNPW. (The full version contains a number of other results.)
false-name-proof combinatorial auctions mechanism design