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arXiv · 2411.14821

Ex-post Stability under Two-Sided Matching: Complexity and Characterization

Haris Aziz·Gergely Csáji·Péter Biró
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Abstract

A probabilistic approach to the stable matching problem has been identified as an important research area with several important open problems. When considering random matchings, ex-post stability is a fundamental stability concept. A prominent open problem is characterizing ex-post stability and establishing its computational complexity. We investigate the computational complexity of testing ex-post stability. Our central result is that when either side has ties in the preferences/priorities, testing ex-post stability is NP-complete. The result even holds if both sides have dichotomous preferences. On the positive side, we give an algorithm using an integer programming approach, that can determine a decomposition with a maximum probability of being weakly stable. We also consider stronger versions of ex-post stability (in particular robust ex-post stability and ex-post strong stability) and prove that they can be tested in polynomial time.

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Haris Aziz, Gergely Csáji, Péter Biró. 2024-11-22. Ex-post Stability under Two-Sided Matching: Complexity and Characterization. https://arxiv.org/abs/2411.14821

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