English

A constructive algorithm for the LLL on permutations

Data Structures and Algorithms 2023-10-13 v1 Combinatorics

Abstract

While there has been significant progress on algorithmic aspects of the Lov\'{a}sz Local Lemma (LLL) in recent years, a noteworthy exception is when the LLL is used in the context of random permutations. The breakthrough algorithm of Moser & Tardos only works in the setting of independent variables, and does not apply in this context. We resolve this by developing a randomized polynomial-time algorithm for such applications. A noteworthy application is for Latin transversals: the best-known general result here (Bissacot et al., improving on Erd\H{o}s and Spencer), states that any n×nn \times n matrix in which each entry appears at most (27/256)n(27/256)n times, has a Latin transversal. We present the first polynomial-time algorithm to construct such a transversal. We also develop RNC algorithms for Latin transversals, rainbow Hamiltonian cycles, strong chromatic number, and hypergraph packing. In addition to efficiently finding a configuration which avoids bad-events, the algorithm of Moser & Tardos has many powerful extensions and properties. These include a well-characterized distribution on the output distribution, parallel algorithms, and a partial resampling variant. We show that our algorithm has nearly all of the same useful properties as the Moser-Tardos algorithm, and present a comparison of this aspect with recent works on the LLL in general probability spaces.

Keywords

Cite

@article{arxiv.1612.02663,
  title  = {A constructive algorithm for the LLL on permutations},
  author = {David G. Harris and Aravind Srinivasan},
  journal= {arXiv preprint arXiv:1612.02663},
  year   = {2023}
}
R2 v1 2026-06-22T17:17:30.112Z