{ "id": "2202.04279", "version": "v1", "published": "2022-02-09T04:53:58.000Z", "updated": "2022-02-09T04:53:58.000Z", "title": "Removable edges in cubic matching covered graphs", "authors": [ "Lu Fuliang", "Qian Jianguo" ], "categories": [ "math.CO" ], "abstract": "An edge $e$ in a matching covered graph $G$ is removable if $G-e$ is matching covered, which was introduced by Lov\\'asz and Plummer in connection with ear decompositions of matching covered graphs. A brick is a non-bipartite matching covered graph without non-trivial tight cuts. The importance of bricks stems from the fact that they are building blocks of matching covered graphs. Carvalho et al. [Ear decompositions of matching covered graphs, Combinatorica, 19(2):151-174, 1999] showed that each brick other than $K_4$ and $\\overline{C_6}$ has $\\Delta-2$ removable edges, where $\\Delta$ is the maximum degree of $G$. We show that every cubic brick $G$ other than $K_4$, $\\overline{C_6}$ and a particular graph of order 8 has a matching of size at least $|V(G)|/7$, each edge of which is removable in $G$. Moreover, if $G$ is a 3-edge-connected near-bipartite cubic graph, then $G$ has a matching of size at least $|V(G)|/2-3$, each edge of which is removable in $G$. The lower bounds for the two sizes of matchings are sharp.", "revisions": [ { "version": "v1", "updated": "2022-02-09T04:53:58.000Z" } ], "analyses": { "keywords": [ "cubic matching covered graphs", "removable edges", "ear decompositions", "near-bipartite cubic graph", "non-trivial tight cuts" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }