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We examine the chromatic index of generalized truncations of graphs and multigraphs.

Combinatorics · Mathematics 2021-09-15 Brian Alspach , Aditya Joshi

We present recent advances in harmonic analysis on infinite graphs. Our approach combines combinatorial tools with new results from the theory of unbounded Hermitian operators in Hilbert space, geometry, boundary constructions, and spectral…

Combinatorics · Mathematics 2020-10-26 Sergey Bezuglyi , Palle E. T. Jorgensen

The studies on $b$-chromatic number attracted much interest since its introduction. In this paper, we discuss the $b$-chromatic number of certain classes of graphs and digraphs. The notion of a new general family of graphs called the…

General Mathematics · Mathematics 2015-11-04 Johan Kok , Naduvath Sudev

The Tutte polynomial is a fundamental invariant of graphs. In this article, we define and study a generalization of the Tutte polynomial for directed graphs, that we name B-polynomial. The B-polynomial has three variables, but when…

Combinatorics · Mathematics 2019-01-01 Jordan Awan , Olivier Bernardi

We study the chromatic symmetric function on graphs, and show that its kernel is spanned by the modular relations. We generalize this result to the chromatic quasisymmetric function on hypergraphic polytopes, a family of generalized…

Combinatorics · Mathematics 2020-03-31 Raul Penaguiao

Total variant of well known graph coloring game is considered. We determine exact values of total game chromatic number for some classes of graphs and show show the strategie for first player to win the game. We also show relation between…

Combinatorics · Mathematics 2012-10-30 Tomasz Bartnicki , Zofia Miechowicz

The structural properties of graphs are usually characterized in terms of invariants, which are functions of graphs that do not depend on the labeling of the nodes. In this paper we study convex graph invariants, which are graph invariants…

Optimization and Control · Mathematics 2012-09-21 Venkat Chandrasekaran , Pablo A. Parrilo , Alan S. Willsky

We study free scalar field theory on a graph, which gives rise to a modified version of discrete Green's function on a graph studied in \cite{CY}. We show that this gives rise to a graph invariant, which is closely related to the 2-dim…

Combinatorics · Mathematics 2015-06-18 An Huang , Shing-Tung Yau , Mei-Heng Yueh

Directed acyclic graphs whose nodes are all the divisors of a positive integer $n$ and arcs $(a,b)$ defined by $a$ divides $b$ are considered. Fourteen graph invariants such as order, size, and the number of paths are investigated for two…

Number Theory · Mathematics 2014-05-22 Sung-Hyuk Cha , Edgar G. DuCasse , Louis V. Quintas

A broader definition of generalized truncations of graphs is introduced followed by an exploration of some standard concepts and parameters with regard to generalized truncations.

Combinatorics · Mathematics 2020-07-10 Brian Alspach , Joshua B. Connor

In this paper, we introduce and study two variants of the chromatic quasisymmetric function of a graph: the total chromatic quasisymmetric function via vertex labeling and via acyclic orientations. The original definition of the chromatic…

Combinatorics · Mathematics 2026-02-27 Laura Colmenarejo , Ian Klein

In this paper we will prove that there exists a covariant functor from the category of schemes to the category of graphs. This functor provides a combination between algebraic varieties and combinatorial graphs so that the invariants…

Algebraic Geometry · Mathematics 2009-07-06 Feng-Wen An

We introduce invariants of spatial graphs related to the Wu invariant and the Simon invariant, and apply them to prove that certain graphs are intrinsically chiral, and to obtain lower bounds for the minimal crossing number of embedded…

Geometric Topology · Mathematics 2019-02-20 Erica Flapan , Will Fletcher , Ryo Nikkuni

We extend the concept of the law of a finite graph to graphings, which are, in general, infinite graphs whose vertices are equipped with the structure of a probability space. By doing this, we obtain a vast array of new unimodular measures.…

Combinatorics · Mathematics 2012-03-13 Igor Artemenko

Graphs constructed to translate some graph problem into another graph problem are usually called auxiliary graphs. Specifically total graphs of simple graphs are used to translate the total colouring problem of the original graph into a…

General Mathematics · Mathematics 2016-02-16 Ravi Goyal , Mahipal Jadeja , Rahul Muthu

Let $P$ be a poset, $inc(P)$ its incomparability graph, and $X_{inc(P)}$ the corresponding chromatic symmetric function, as defined by Stanley in {\em Adv. Math.}, {\bf 111} (1995) pp.~166--194. Certain conditions on $P$ imply that the…

Combinatorics · Mathematics 2021-05-04 Mark Skandera

The theory of graphons has proven to be a powerful tool in many areas of graph theory. In this paper, we introduce several foundational aspects of the theory of digraphons -- asymmetric two-variable functions that arise as limits of…

Combinatorics · Mathematics 2025-12-16 Jan Hladký , Petr Savický

For time-reversal invariant graphs we prove the Bohigas-Giannoni-Schmit conjecture in its most general form: For graphs that are mixing in the classical limit, all spectral correlation functions coincide with those of the Gaussian…

Mathematical Physics · Physics 2015-06-18 Z. Pluhar , H. A. Weidenmueller

A topological index of a graph $G$ is a real number which is preserved under isomorphism. Extensive studies on certain polynomials related to these topological indices have also been done recently. In a similar way, chromatic versions of…

General Mathematics · Mathematics 2018-11-02 Sudev Naduvath

Coloured graphical models are Gaussian statistical models determined by an undirected coloured graph. These models can be described by linear spaces of symmetric matrices. We outline a relationship between the symmetries of the graph and…

Algebraic Geometry · Mathematics 2025-01-14 Isobel Davies , Orlando Marigliano