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Main Authors: Bogdanov, Ilya I., Petrov, Fedor, Sadovnichiy, Anton, Ushakov, Fedor
Format: Preprint
Published: 2026
Subjects:
Online Access:https://arxiv.org/abs/2603.18253
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author Bogdanov, Ilya I.
Petrov, Fedor
Sadovnichiy, Anton
Ushakov, Fedor
author_facet Bogdanov, Ilya I.
Petrov, Fedor
Sadovnichiy, Anton
Ushakov, Fedor
contents In 2019, P. Higgins formulated [1] a question about bipartite graphs (see Conjecture 1 below); this question arises in the study of regular finite semigroups. F. V. Petrov formulated [2] another combinatorial conjecture (Conjecture 3); Conjecture 3 implies Conjecture 1 and seems simple itself. However, both conjectures remain unproven in the general case. In the present paper, some special cases are proved, Conjecture 4 is formulated in the same spirit, and some of its special cases are proved. In addition, Conjecture 1 is reduced to a matrix inequality (Conjecture 5); this inequality is, in turn, also proved in a special case.
format Preprint
id arxiv_https___arxiv_org_abs_2603_18253
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Biregular bipartite labeled multigraphs and perfect matchings in bipartite tensor products
Bogdanov, Ilya I.
Petrov, Fedor
Sadovnichiy, Anton
Ushakov, Fedor
Combinatorics
In 2019, P. Higgins formulated [1] a question about bipartite graphs (see Conjecture 1 below); this question arises in the study of regular finite semigroups. F. V. Petrov formulated [2] another combinatorial conjecture (Conjecture 3); Conjecture 3 implies Conjecture 1 and seems simple itself. However, both conjectures remain unproven in the general case. In the present paper, some special cases are proved, Conjecture 4 is formulated in the same spirit, and some of its special cases are proved. In addition, Conjecture 1 is reduced to a matrix inequality (Conjecture 5); this inequality is, in turn, also proved in a special case.
title Biregular bipartite labeled multigraphs and perfect matchings in bipartite tensor products
topic Combinatorics
url https://arxiv.org/abs/2603.18253