Optimal Collusion-Proof Auctions

We study an optimal collusion-proof auction in an environment where subsets of bidders may collude not just on their bids but also on their participation. Despite their ability to collude on participation, informational asymmetry facing the potential colluders can be exploited significantly to weaken their collusive power. The second-best auction --- i.e., the optimal auction in a collusion-free environment --- can be made collusion-proof, if at least one bidder is not collusive, or there are multiple bidding cartels, or the second-best outcome involves a nontrivial probability of the object not being sold. In case the second-best outcome is not weak collusion-proof implementable, we characterize an optimal collusion-proof auction. This auction involves nontrivial exclusion of collusive bidders --- i.e., the object is not sold to any collusive bidder with positive probability.

Post-Adoption Behavior of Mobile Internet Users: A Model-Based Comparison between Continuers and Discontinuers

Many mobile Internet users are not continuing to use mobile Internet services after initial use. This study aims to explore how such users (discontinuers) differ from ongoing users (continuers) in terms of accepting mobile Internet technology. We propose an adoption model for the mobile Internet consisting of seven critical factors. An on-line survey was conducted on the basis of this model to compare continuers and discontinuers. The survey results show that discontinuers are more sensitive to usefulness and social influences in using mobile Internet services, while continuers are more sensitive to ubiquitous connectivity

Generalized reduced-form auctions: a network-flow approach

We develop a network-flow approach for characterizing interim-allocation rules that can be implemented by ex post allocations. Our method can be used to characterize feasible interim allocations in general multi-unit auctions where agents face capacity constraints, both ceilings and floors. Applications include a variety of settings of practical interest, ranging from individual and group-specific capacity constraints, set-aside sale, partnership dissolution, and government license reallocation.Reduced-form auctions, network-flow approach, feasible circulation flow, paramodular capacity constraints