English

Size and spectral conditions for a graph with given minimum degree to be $k$-$d$-critical

Combinatorics 2026-05-14 v1

Abstract

A kk-matching in a graph GG is defined as a function f:E(G){0,1,,k}f:E(G) \rightarrow \{0,1,\ldots,k\} satisfying eEG(v)f(e)\sum_{e\in E_G(v)} f(e) k\leq k for each vertex vV(G)v\in V(G), where EG(v)E_G(v) denotes the set of edges incident to vv in GG. For 1dk1\leq d\leq k and dV(G) (mod 2)d \equiv |V(G)|~(\mathrm{mod}~2), if for any vV(G) v \in V(G), there exists a kk-matching ff such that eEG(v)f(e)=kd\sum_{e\in E_G(v)}f(e)=k-d and eEG(u)f(e)=k for any uV(G){v}\sum_{e\in E_G(u)}f(e)=k \text{ for any } u\in V(G)-\{v\}, then GG is kk-dd-critical. A graph GG of odd order (resp. even order) is generalized factor-critical (resp. generalized bicritical) if the empty set is the unique set attaining the maximum value in kk-Berge-Tutte-formula of GG. In this paper, we provide sharp sufficient conditions in terms of size or spectral radius respectively for a graph GG to be kk-dd-critical, generalized factor-critical and generalized bicritical with minimum degree.

Keywords

Cite

@article{arxiv.2605.13198,
  title  = {Size and spectral conditions for a graph with given minimum degree to be $k$-$d$-critical},
  author = {Zhenhao Zhang and Xiaogang Liu and Ligong Wang},
  journal= {arXiv preprint arXiv:2605.13198},
  year   = {2026}
}