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On corona of Konig-Egervary graphs

Combinatorics 2024-11-21 v1 Discrete Mathematics

Abstract

Let α(G)\alpha(G) denote the cardinality of a maximum independent set and μ(G)\mu(G) be the size of a maximum matching of a graph G=(V,E)G=\left( V,E\right) . If α(G)+μ(G)=V\alpha(G)+\mu(G)=\left\vert V\right\vert , then GG is a K\"{o}nig-Egerv\'{a}ry graph, and GG is a 11-K\"{o}nig-Egerv\'{a}ry graph whenever α(G)+μ(G)=V1\alpha(G)+\mu(G)=\left\vert V\right\vert -1. The corona HXH\circ\mathcal{X} of a graph HH and a family of graphs X={Xi:1iV(H)}\mathcal{X}=\left\{ X_{i}:1\leq i\leq\left\vert V(H)\right\vert \right\} is obtained by joining each vertex viv_{i} of HH to all the vertices of the corresponding graph Xi,i=1,2,...,V(H)X_{i},i=1,2,...,\left\vert V(H)\right\vert . In this paper we completely characterize graphs whose coronas are kk-K\"{o}nig-Egerv\'{a}ry graphs, where k{0,1}k\in\left\{ 0,1\right\} .

Keywords

Cite

@article{arxiv.2411.12863,
  title  = {On corona of Konig-Egervary graphs},
  author = {Vadim E. Levit and Eugen Mandrescu},
  journal= {arXiv preprint arXiv:2411.12863},
  year   = {2024}
}

Comments

11 pages, 3 figures