English

A P\'{o}sa-type condition of potentially $_3C_\ell$-graphic sequences

Combinatorics 2019-12-03 v1

Abstract

A non-increasing sequence π=(d1,,dn)\pi=(d_1,\ldots,d_n) of nonnegative integers is said to be graphic if it is realizable by a simple graph GG on nn vertices. A graphic sequence π=(d1,,dn)\pi=(d_1,\ldots,d_n) is said to be potentially 3C_3C_\ell-graphic if there is a realization of π\pi containing cycles of every length rr, 3r3\le r\le \ell. It is well-known that if the non-increasing degree sequence (d1,,d)(d_1,\ldots,d_\ell) of a graph GG on \ell vertices satisfies the P\'{o}sa condition that d+1ii+1d_{\ell+1-i}\ge i+1 for every ii with 1i<21\le i<\frac{\ell}{2}, then GG is either pancyclic or bipartite. In this paper, we obtain a P\'{o}sa-type condition of potentially 3C_3C_\ell-graphic sequences, that is, we prove that if 5\ell\ge 5 is an integer, nn\ge \ell and π=(d1,,dn)\pi=(d_1,\ldots,d_n) is a graphic sequence with d+1ii+1d_{\ell+1-i}\ge i+1 for every ii with 1i<21\le i<\frac{\ell}{2}, then π\pi is potentially 3C_3C_\ell-graphic. This result improves a Dirac-type condition of potentially 3C_3C_\ell-graphic sequences due to Yin et al. [Appl. Math. Comput., 353 (2019) 88--94], and asymptotically answers a problem due to Li et al. [Adv. Math., 33 (2004) 273--283]. As an application, this result also completely implies the value σ(C,n)\sigma(C_\ell,n) for 5\ell\ge 5 and nn\ge \ell, improving the result of Lai [J. Combin. Math. Combin. Comput., 49 (2004) 57--64].

Keywords

Cite

@article{arxiv.1912.00309,
  title  = {A P\'{o}sa-type condition of potentially $_3C_\ell$-graphic sequences},
  author = {Guang-Ming Li and Jian-Hua Yin},
  journal= {arXiv preprint arXiv:1912.00309},
  year   = {2019}
}