Cubic bricks that every b-invariant edge is forcing

Fuente: arXiv
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Main Authors: Zhang, Yaxian, Lu, Fuliang, Zhang, Heping
Format: Preprint
Published: 2024
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author Zhang, Yaxian
Lu, Fuliang
Zhang, Heping
author_facet Zhang, Yaxian
Lu, Fuliang
Zhang, Heping
contents A connected graph G is matching covered if every edge lies in some perfect matching of G. Lovasz proved that every matching covered graph G can be uniquely decomposed into a list of bricks (nonbipartite) and braces (bipartite) up to multiple edges. Denote by b(G) the number of bricks of G. An edge e of G is removable if G-e is also matching covered, and solitary (or forcing) if after the removal of the two end vertices of e, the left graph has a unique perfect matching. Furthermore, a removable edge e of a brick G is b-invariant if b(G-e) = 1. Lucchesi and Murty proposed a problem of characterizing bricks, distinct from K4, the prism and the Petersen graph, in which every b-invariant edge is forcing. We answer the problem for cubic bricks by showing that there are exactly ten cubic bricks, including K4, the prism and the Petersen graph, every b-invariant edge of which is forcing.
format Preprint
id arxiv_https___arxiv_org_abs_2411_17295
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Cubic bricks that every b-invariant edge is forcing
Zhang, Yaxian
Lu, Fuliang
Zhang, Heping
Combinatorics
A connected graph G is matching covered if every edge lies in some perfect matching of G. Lovasz proved that every matching covered graph G can be uniquely decomposed into a list of bricks (nonbipartite) and braces (bipartite) up to multiple edges. Denote by b(G) the number of bricks of G. An edge e of G is removable if G-e is also matching covered, and solitary (or forcing) if after the removal of the two end vertices of e, the left graph has a unique perfect matching. Furthermore, a removable edge e of a brick G is b-invariant if b(G-e) = 1. Lucchesi and Murty proposed a problem of characterizing bricks, distinct from K4, the prism and the Petersen graph, in which every b-invariant edge is forcing. We answer the problem for cubic bricks by showing that there are exactly ten cubic bricks, including K4, the prism and the Petersen graph, every b-invariant edge of which is forcing.
title Cubic bricks that every b-invariant edge is forcing
topic Combinatorics
url https://arxiv.org/abs/2411.17295