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We compute numerically the homology of several graph complexes in low loop orders, extending previous results.

Quantum Algebra · Mathematics 2023-12-21 Simon Brun , Thomas Willwacher

Kang and Park recently showed that every cubic (loopless) multigraph is incidence 6-choosable [On incidence choosability of cubic graphs. \emph{arXiv}, April 2018]. Equivalently, every bipartite graph obtained by subdividing once every edge…

Combinatorics · Mathematics 2018-08-06 Petru Valicov

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

The modern theory of homogeneous structures begins with the work of Roland Fra\"iss\'e. The theory developed in the last seventy years is placed in the border area between combinatorics, model theory, algebra, and analysis. We turn our…

Combinatorics · Mathematics 2026-01-13 Bojana Pavlica , Christian Pech , Maja Pech

The set of semialgebraic graphs having countable list-chromatic numbers is characterized. Some other related sets of graphs having countable list-chromatic numbers also are.

Combinatorics · Mathematics 2015-05-25 James H. Schmerl

A bipartite covering of a (multi)graph $G$ is a collection of bipartite graphs, so that each edge of $G$ belongs to at least one of them. The capacity of the covering is the sum of the numbers of vertices of these bipartite graphs. In this…

Combinatorics · Mathematics 2023-08-01 Noga Alon

Homomorphically full graphs are those for which every homomorphic image is isomorphic to a subgraph. We extend the definition of homomorphically full to oriented graphs in two different ways. For the first of these, we show that…

Discrete Mathematics · Computer Science 2024-02-14 Thomas Bellitto , Christopher Duffy , Gary MacGillivray

We classify all normal edge ideals of edge-weighted graphs.

Commutative Algebra · Mathematics 2024-07-24 Thanh Vu , Guangjun Zhu

In this paper, we give a class of reconstructible graphs.

Combinatorics · Mathematics 2007-05-23 Tetsuya Hosaka

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

The Unfriendly Partition Conjecture posits that every countable graph admits a 2-colouring in which for each vertex there are at least as many bichromatic edges containing that vertex as monochromatic ones. This is not known in general, but…

Combinatorics · Mathematics 2023-03-22 John Haslegrave

We examine ordered graphs, defined as graphs with linearly ordered vertices, from the perspective of homomorphisms (and colorings) and their complexities. We demonstrate the corresponding computational and parameterized complexities, along…

Computational Complexity · Computer Science 2025-12-01 Michal Čertík , Andreas Emil Feldmann , Jaroslav Nešetřil , Paweł Rzążewski

Unigraphs are graphs identifiable up to isomorphism from their degree sequences. Given a class $\mathcal{A}$ of graphs, we define the class of $\mathcal{A}$-unigraphs to be graphs identifiable from degree sequence and membership in…

Combinatorics · Mathematics 2024-06-07 R. Whitman

We give a recursion formula to generate all equivalence classes of biconnected graphs with coefficients given by the inverses of the orders of their groups of automorphisms. We give a linear map to produce a connected graph with say, u,…

Combinatorics · Mathematics 2013-03-14 Angela Mestre

In this paper, we completely characterize the niche graphs of bipartite tournaments and find their interesting properties.

Combinatorics · Mathematics 2018-10-15 Soogang Eoh , Jihoon Choi , Suh-Ryung Kim , Miok Oh

In this paper, we investigate odd graceful graph, odd strongly harmonious graph, bipartite graph and their relationship. We proved following results: (1) if G is odd strongly harmonious graph, then G is odd graceful graph ;(2) if G is…

Combinatorics · Mathematics 2020-01-06 Xiuying Wang , Ying Zhoua , Haihong Wanga , Chunfeng Liu

A directed graph is set-homogeneous if, whenever U and V are isomorphic finite subdigraphs, there is an automorphism g of the digraph with U^g=V. Here, extending work of Lachlan on finite homogeneous digraphs, we classify finite…

Combinatorics · Mathematics 2010-11-19 Robert Gray , Dugald Macpherson , Cheryl E. Praeger , Gordon F. Royle

In this paper we determine all the bipartite graphs with the maximum sum of squares of degrees among the ones with a given number of vertices and edges.

Combinatorics · Mathematics 2011-09-23 Shenggui Zhang , Chuncao Zhou

The bipartition polynomial of a graph is a generalization of many other graph polynomials, including the domination, Ising, matching, independence, cut, and Euler polynomial. We show in this paper that it is also a powerful tool for proving…

Combinatorics · Mathematics 2017-02-14 Seongmin Ok , Peter Tittmann

The graph packing problem is a well-known area in graph theory. We consider a bipartite version and give almost tight conditions on the packability of two bipartite sequences.

Combinatorics · Mathematics 2017-05-03 Bálint Vásárhelyi