In various models of matching markets, substitutable preferences constitute the largest domain for which stable matchings are guaranteed to exist. Recently, Hatfield et al. (2012) have proposed an efficient algorithm to test substitutability of strict preferences. In this note we show how the...

Rationalizability and similar notions of consistency have proved to be highly problematic in the context of social choice, as witnessed by a range of impossibility results, among which Arrow[modifier letter apostrophe]s is the most prominent. We propose to rationalize choice functions by...

A minimal requirement on allocative efficiency in the social sciences is Pareto optimality. In this paper, we identify a close structural connection between Pareto optimality and perfection that has various algorithmic consequences for coalition formation. Based on this insight, we formulate the...