Published Papers:
Title: Consistency in One-Sided Assignment Problems (Download ARTICLE / SLIDES).
Co-author: Bettina Klaus.
Journal: Social Choice and Welfare, v.35(3), September 2010, pp. 415-433.
Abstract: One-sided assignment problems combine important features of two well-known matching models. First, as in roommate problems, any two agents can be matched and second, as in two-sided assignment problems, the division of payoffs to agents is flexible as part of the solution. We take a similar approach to one-sided assignment problems as Sasaki (Int J Game Theory 24:373–397, 1995) for two-sided assignment problems, and we analyze various desirable properties of solutions including consistency and weak pairwise-monotonicity. We show that for the class of solvable one-sided assignment problems (i.e., the subset of one-sided assignment problems with a non-empty core), if a subsolution of the core satisfies [Pareto indifference and consistency] or [invariance with respect to unmatching dummy pairs, continuity, and consistency], then it coincides with the core (Theorems 1 and 2). However, we also prove that on the class of all one-sided assignment problems (solvable or not), no solution satisfies consistency and coincides with the core whenever the core is non-empty (Theorem 4). Finally, we comment on the difficulty in obtaining further positive results for the class of solvable one-sided assignment problems in line with Sasaki's (1995) characterizations of the core for two-sided assignment problems.
Working Papers:
Title: Stability and Competitive Equilibrium in Trading Networks (Download ARTICLE).
Co-authors: John William Hatfield, Scott Duke Kominers, Michael Ostrovsky, Alexander Westkamp.
Mimeo: TBA.
Abstract: In models of matching in networks, when transfers are not allowed or are only allowed to be discrete, both substitutability of preferences and supply chain structure of the contractual set are required for the guaranteed existence of stable outcomes. We show that when continuous transfers are allowed and utility is quasilinear, the substitutability of preferences is on its own both sufficient and necessary for the guaranteed existence of stable outcomes. Furthermore, when preferences are substitutable, the set of stable outcomes is equivalent to the set of competitive equilibria, and all stable allocations are efficient.
Title: Intellectual Influence: Quality versus Quantity (Download ARTICLE).
Co-authors: Laszlo Koczy.
Mimeo: TBA.
Abstract: To take development and budgeting decisions for research activities the officials in charge need to constantly evaluate and assess the quality of research. Over the years a handful of scoring methods for academic journals have been proposed. Discussing the most prominent methods (de facto standards) we show that they cannot distinguish quality from quantity at article level and that they are inherently biased against journals publishing more articles. If we consider the length of a journal by the number of pages or characters, then all methods are biased against lengthier journals. The systematic bias we find is analytically tractable and implies that the methods are manipulable. We show that the strategies for successful manipulation are relatively easy to infer and implement. The implications of our findings extend beyond the evaluation of academic research, to related settings like the ranking of web domains. Non-manipulable methods for measuring intellectual influence exist.