Multi-object auction design beyond quasi-linearity: Leading examples

In multi-object auction models with unit demand agents, two standard assumptions are the quasi-linearity of utility functions and coincidence between price increment valuation unit. Under these assumptions, exact ascending Demange et al. (1986), sealed-bid Vickrey auction, as well approximate (1986) identify minimum equilibrium (MPE) while elegantly exhibiting efficiency incentive-compatibility. We demonstrate that auctions fail to MPEs substantially inefficient manipulable if dropped. also discuss implications our negative results for multi-unit matching contracts models.