On the minimum number of spanning trees in cubic multigraphs
Author(s) -
Zbigniew R. Bogdanowicz
Publication year - 2018
Publication title -
discussiones mathematicae graph theory
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.476
H-Index - 19
eISSN - 2083-5892
pISSN - 1234-3099
DOI - 10.7151/dmgt.2123
Subject(s) - combinatorics , spanning tree , mathematics , conjecture , graph , cubic graph , order (exchange) , minimum degree spanning tree , degree (music) , discrete mathematics , physics , line graph , voltage graph , finance , acoustics , economics
Let G2n, H2n be two non-isomorphic connected cubic multigraphs of order 2n with parallel edges permitted but without loops. Let t(G2n), t (H2n) denote the number of spanning trees in G2n, H2n, respectively. We prove that for n ≥ 3 there is the unique G2n such that t(G2n) < t(H2n) for any H2n. Furthermore, we prove that such a graph has t(G2n = 522n−3 spanning trees. Based on our results we give a conjecture for the unique r-regular connected graph H2n of order 2n and odd degree r that minimizes the number of spanning trees.
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