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Fractional chromatic number of a random subgraph

Combinatorics 2018-07-18 v1

Abstract

It is well known that a random subgraph of the complete graph KnK_n has chromatic number Θ(n/logn)\Theta(n/\log n) w.h.p. Boris Bukh asked whether the same holds for a random subgraph of any nn-chromatic graph, at least in expectation. In this paper it is shown that for every graph, whose fractional chromatic number is at least nn, the fractional chromatic number of its random subgraph is at least n/(8log2(4n))n/(8\log_2(4n)) with probability more than 112n1-\frac{1}{2n}. This gives the affirmative answer for a strengthening of Bukh's question for the fractional chromatic number.

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Cite

@article{arxiv.1807.06285,
  title  = {Fractional chromatic number of a random subgraph},
  author = {Bojan Mohar and Hehui Wu},
  journal= {arXiv preprint arXiv:1807.06285},
  year   = {2018}
}

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