,
Dor Minzer
,
Muli Safra
Creative Commons Attribution 4.0 International license
A graph G = (V,E) is said to be (k,δ) almost colorable if there is a subset of vertices V' ⊆ V of size at least (1-δ)|V| such that the induced subgraph of G on V' is k-colorable. We prove that for all k, there exists δ > 0 such for all ε > 0, given a graph G it is NP-hard (under randomized reductions) to distinguish between: 1) Yes case: G is (3,ε) almost colorable. 2) No case: G is not (k,δ) almost colorable. This improves upon an earlier result of Khot et al. [Irit Dinur et al., 2018], who showed a weaker result wherein in the "yes case" the graph is (4,ε) almost colorable.
@InProceedings{hecht_et_al:LIPIcs.APPROX/RANDOM.2023.51,
author = {Hecht, Yahli and Minzer, Dor and Safra, Muli},
title = {{NP-Hardness of Almost Coloring Almost 3-Colorable Graphs}},
booktitle = {Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques (APPROX/RANDOM 2023)},
pages = {51:1--51:12},
series = {Leibniz International Proceedings in Informatics (LIPIcs)},
ISBN = {978-3-95977-296-9},
ISSN = {1868-8969},
year = {2023},
volume = {275},
editor = {Megow, Nicole and Smith, Adam},
publisher = {Schloss Dagstuhl -- Leibniz-Zentrum f{\"u}r Informatik},
address = {Dagstuhl, Germany},
URL = {https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.APPROX/RANDOM.2023.51},
URN = {urn:nbn:de:0030-drops-188761},
doi = {10.4230/LIPIcs.APPROX/RANDOM.2023.51},
annote = {Keywords: PCP, Hardness of approximation}
}