English

The number of cliques in graphs covered by long cycles

Combinatorics 2021-12-02 v1

Abstract

Let GG be a 2-connected nn-vertex graph and Ns(G)N_s(G) be the total number of ss-cliques in GG. Let k4k\ge 4 and s2s\ge 2 be integers. In this paper, we show that if GG has an edge ee which is not on any cycle of length at least kk, then Ns(G)r(k1s)+(t+2s)N_s(G)\le r{k-1\choose s}+{t+2\choose s}, where n2=r(k3)+tn-2=r(k-3)+t and 0tk40\le t\le k-4. This result settles a conjecture of Ma and Yuan and provides a clique version of a theorem of Fan, Wang and Lv. As a direct corollary, if Ns(G)>r(k1s)+(t+2s)N_s(G)> r{k-1\choose s}+{t+2\choose s}, every edge of GG is covered by a cycle of length at least kk.

Keywords

Cite

@article{arxiv.2112.00070,
  title  = {The number of cliques in graphs covered by long cycles},
  author = {Naidan Ji and Dong Ye},
  journal= {arXiv preprint arXiv:2112.00070},
  year   = {2021}
}

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