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In this paper, we introduce a corresponding between bipartite graphs with a perfect matching and digraphs, which implicates an equivalent relation between the extendibility of bipartite graphs and the strongly connectivity of digraphs. Such…

Combinatorics · Mathematics 2010-11-22 Zan-Bo Zhang , Dingjun Lou

Bivariate P-polynomial association scheme of type $(\alpha,\beta)$ are defined as a generalization of the P-polynomial association schemes. This generalization is shown to be equivalent to a set of conditions on the intersection parameters.…

Combinatorics · Mathematics 2024-07-10 P. -A. Bernard , N. Crampe , L. Poulain d'Andecy , L. Vinet , M. Zaimi

We determine which properties of 2-layer drawings characterise bipartite graphs of bounded pathwidth.

Combinatorics · Mathematics 2022-07-15 David R. Wood

An association scheme is $P$-polynomial if and only if it consists of the distance matrices of a distance-regular graph. Recently, bivariate $P$-polynomial association schemes of type $(\alpha,\beta)$ were introduced by Bernard et al., and…

Combinatorics · Mathematics 2024-01-30 Pierre-Antoine Bernard , Nicolas Crampe , Luc Vinet , Meri Zaimi , Xiaohong Zhang

We introduce the notion of P-polynomial coherent configurations and show that they can have at most two fibres. We then introduce a class of two-fibre coherent configurations which have two distinguished bases for the coherent algebra,…

Combinatorics · Mathematics 2024-12-02 Sabrina Lato

In this paper we study the main characteristics of some evaluation codes parameterized by the edges of a bipartite graph with a perfect matching.

Combinatorics · Mathematics 2022-10-04 Manuel Gonzalez Sarabia , Rafael H. Villarreal

Intuitively speaking, a bipartite graph is mirror if it can be drawn in the Cartesian plane in such a way that, the vertices of one stable are points in x=0, the vertices of the other stable set are points in x=1, the edges are straight…

Combinatorics · Mathematics 2013-12-13 Susana-Clara López , Francesc-Antoni Muntaner-Batle

We present novel results related to isomorphic resonance graphs of 2-connected outerplane bipartite graphs. As the main result, we provide a structure characterization for 2-connected outerplane bipartite graphs with isomorphic resonance…

Combinatorics · Mathematics 2025-02-07 Simon Brezovnik , Zhongyuan Che , Niko Tratnik , Petra Žigert Pleteršek

We call a 2-partite digraph D homogeneous if every isomorphism between finite induced subdigraphs that respects the 2-partition of D extends to an automorphism of D that does the same. In this note, we classify the homogeneous 2-partite…

Combinatorics · Mathematics 2013-11-21 Matthias Hamann

We introduce a new notation for representing labeled regular bipartite graphs of arbitrary degree. Several enumeration problems for labeled and unlabeled regular bipartite graphs have been introduced. A general algorithm for enumerating all…

Discrete Mathematics · Computer Science 2015-12-31 Vivek S. Nittoor

We present an algorithm for determining whether a bipartite graph $G$ is 2-chordal (formerly doubly chordal bipartite). At its core this algorithm is an extension of the existing efficient algorithm for determining whether a graph is…

Combinatorics · Mathematics 2021-04-13 Austin Alderete

We show that if the two parts of a finite bipartite graph have the same degree sequence, then there is a bipartite graph, with the same degree sequences, which is symmetric, in that it has an involutive graph automorphism that interchanges…

Combinatorics · Mathematics 2014-07-07 Grant Cairns , Stacey Mendan

It is not hard to find many complete bipartite graphs which are not determined by their spectra. We show that the graph obtained by deleting an edge from a complete bipartite graph is determined by its spectrum. We provide some graphs, each…

Combinatorics · Mathematics 2016-01-27 Chia-an Liu , Chih-wen Weng

It is well known that a plane graph is Eulerian if and only if its geometric dual is bipartite. We extend this result to partial duals of plane graphs. We then characterize all bipartite partial duals of a plane graph in terms of oriented…

Combinatorics · Mathematics 2013-11-18 Stephen Huggett , Iain Moffatt

Biregular bipartite graphs have been proven to have similar edge distributions to random bipartite graphs and thus have nice pseudorandomness and expansion properties. Thus it is quite desirable to find a biregular bipartite spanning…

Combinatorics · Mathematics 2024-10-29 Dandan Fan , Xiaofeng Gu , Huiqiu Lin

Let $G$ be a group and $L(G)$ be the set of all subgroups of $G$. We introduce a bipartite graph $\mathcal{B}(G)$ on $G$ whose vertex set is the union of two sets $G \times G$ and $L(G)$, and two vertices $(a, b) \in G \times G$ and $H \in…

Group Theory · Mathematics 2024-12-10 Shrabani Das , Ahmad Erfanian , Rajat Kanti Nath

We consider the line graph of a pure simplicial complex. We prove that, as in the case of line graphs of simple graphs, one can compute the second graded Betti number of the facet ideal of a pure simplicial complex in terms of the…

Commutative Algebra · Mathematics 2025-09-16 Anda Olteanu

Each finite and connected bipartite graph induces a finite collection of non-isomorphic dessins d'enfants, that is, $2$-cell embeddings of it into some closed orientable surface. We describe an algorithm to compute all these dessins…

Combinatorics · Mathematics 2017-08-24 Ruben A. Hidalgo

Recent investigations in computational biology have focused on a family of 2-colored digraphs, called 2-colored best match graphs, which naturally arise from rooted phylogenetic trees. Actually the defining properties of such graphs are…

Combinatorics · Mathematics 2020-12-01 Annachiara Korchmaros

Let $G$ be a finite group. The bipartite divisor graph for the set of irreducible complex character degrees is the undirected graph with vertex set consisting of the prime numbers dividing some character degree and of the non-identity…

Group Theory · Mathematics 2019-06-21 Roghayeh Hafezieh , Pablo Spiga
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