,
Vincent Cohen-Addad
,
Tommaso D'Orsi
,
Anupam Gupta
,
Euiwoong Lee
,
Debmalya Panigrahi
,
Sijin Peng
Creative Commons Attribution 4.0 International license
In this paper, we study the parameterized complexity of local search, whose goal is to find a good nearby solution from the given current solution. Formally, given an optimization problem where the goal is to find the largest feasible subset S of a universe U, the new input consists of a current solution P (not necessarily feasible) as well as an ordinary input for the problem. Given the existence of a feasible solution S^*, the goal is to find a feasible solution as good as S^* in parameterized time f(k)⋅n^O(1), where k denotes the distance |PΔ S^*|. This model generalizes numerous classical parameterized optimization problems whose parameter k is the minimum number of elements removed from U to make it feasible, which corresponds to the case P = U. We apply this model to widely studied Constraint Satisfaction Problems (CSPs), where U is the set of constraints, and a subset U' of constraints is feasible if there is an assignment to the variables satisfying all constraints in U'. We give a complete characterization of the parameterized complexity of all boolean-alphabet symmetric CSPs, where the predicate’s acceptance depends on the number of true literals.
@InProceedings{anand_et_al:LIPIcs.IPEC.2025.26,
author = {Anand, Aditya and Cohen-Addad, Vincent and D'Orsi, Tommaso and Gupta, Anupam and Lee, Euiwoong and Panigrahi, Debmalya and Peng, Sijin},
title = {{Complexity of Local Search for CSPs Parameterized by Constraint Difference}},
booktitle = {20th International Symposium on Parameterized and Exact Computation (IPEC 2025)},
pages = {26:1--26:17},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-407-9},
ISSN = {1868-8969},
year = {2025},
volume = {358},
editor = {Agrawal, Akanksha and van Leeuwen, Erik Jan},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.IPEC.2025.26},
URN = {urn:nbn:de:0030-drops-251586},
doi = {10.4230/LIPIcs.IPEC.2025.26},
annote = {Keywords: Constraint Satisfaction Problems, Parameterized Local Search, Optimization}
}