{ "id": "1905.07301", "version": "v1", "published": "2019-05-17T14:42:43.000Z", "updated": "2019-05-17T14:42:43.000Z", "title": "$b$-invariant edges in cubic near-bipartite brick", "authors": [ "Fuliang Lu", "Xing Feng", "Yan Wang" ], "categories": [ "math.CO" ], "abstract": "A brick is a non-bipartite graph without non-trivial tight cuts. Bricks are building blocks of matching covered graphs. We say that an edge $e$ in a brick $G$ is $b$-invariant if $G-e$ is matching covered and it contains exactly one brick. Kothari, Carvalho, Lucchesi, and Little shown that each essentially 4-edge-connected cubic non-near-bipartite brick $G$, distinct from Petersen graph, has at least $|V(G)|$ $b$-invariant edges. Moreover, they made a conjecture: every essentially 4-edge-connected cubic near-bipartite brick $G$, distinct from $K_4$, has at least $|V(G)|/2$ $b$-invariant edges. We confirm the conjecture in this paper. Furthermore, we characterized when equality holds.", "revisions": [ { "version": "v1", "updated": "2019-05-17T14:42:43.000Z" } ], "analyses": { "keywords": [ "cubic near-bipartite brick", "invariant edges", "non-trivial tight cuts", "cubic non-near-bipartite brick", "non-bipartite graph" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }