Simple dominance of fixed priority top trading cycles

TL;DR

This paper characterizes all fixed priority top trading cycle rules that can be implemented through simply dominant mechanisms in assignment problems without monetary transfers, considering models with and without outside options.

Contribution

It provides a complete characterization of simply dominant FPTTC rules and introduces simple strategy-proofness to address time-inconsistent preferences.

Findings

All simply dominant FPTTC rules are characterized in both models.

Introduction of simple strategy-proofness clarifies agents' incentives.

Analysis covers models with and without outside options.

Abstract

We study the implementation of fixed priority top trading cycles (FPTTC) rules via simply dominant mechanisms (Pycia and Troyan, 2019) in the context of assignment problems, where agents are to be assigned at most one indivisible object and monetary transfers are not allowed. We consider both models - with and without outside options, and characterize all simply dominant FPTTC rules in both models. We further introduce the notion of simple strategy-proofness to resolve the issue with agents being concerned about having time-inconsistent preferences, and discuss its relation with simple dominance.