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A class of graphs admits an adjacency labeling scheme of size $b(n)$, if the vertices in each of its $n$-vertex graphs can be assigned binary strings (called labels) of length $b(n)$ so that the adjacency of two vertices can be determined…

Combinatorics · Mathematics 2024-02-21 Édouard Bonnet , Julien Duron , John Sylvester , Viktor Zamaraev , Maksim Zhukovskii

We introduce a new one-variable polynomial invariant of graphs, which we call the skew characteristic polynomial. For an oriented simple graph, this is just the characteristic polynomial of its anti-symmetric adjacency matrix. For…

Combinatorics · Mathematics 2024-02-14 R. Dogra , S. Lando

We show that a simple scoring-based tie-breaking can help improve lower bounds for the expansion (aka isoperimetric number) of random regular graphs with small even degrees. Specifically, for degrees 4, 6 and 8, we show that, with high…

Combinatorics · Mathematics 2026-04-02 Pasin Manurangsi

We provide some conditions for the graph of a Hoelder-continuous function on \bar{D}, where \bar{D} is a closed disc in the complex plane, to be polynomially convex. Almost all sufficient conditions known to date --- provided the function…

Complex Variables · Mathematics 2015-08-28 Gautam Bharali

We revisit the classical question of the relationship between the diameter of a graph and its expansion properties. One direction is well understood: expander graphs exhibit essentially the lowest possible diameter. We focus on the reverse…

Combinatorics · Mathematics 2017-11-23 Michael Dinitz , Michael Schapira , Gal Shahaf

For each commutative, graded algebra with finite dimension in each degree, we construct a graded cohomology theory for graphs whose graded Euler characteristic is the chromatic polynomial of the graph. This extends our previous work which…

Quantum Algebra · Mathematics 2007-05-23 Laure Helme-Guizon , Yongwu Rong

We give a method of generating strongly polynomial sequences of graphs, i.e., sequences $(H_{\mathbf{k}})$ indexed by a multivariate parameter $\mathbf{k}=(k_1,\ldots, k_h)$ such that, for each fixed graph $G$, there is a multivariate…

Combinatorics · Mathematics 2013-08-20 Delia Garijo , Andrew Goodall , Jaroslav Nesetril

This paper describes how many known graph polynomials arise from the coefficients of chromatic symmetric function expansions in different bases, and studies a new polynomial arising by expanding over a basis given by chromatic symmetric…

Combinatorics · Mathematics 2022-04-18 William Chan , Logan Crew

The scramble number of a graph, a natural generalization of bramble number, is an invariant recently developed to study chip-firing games and graph gonality. We introduce the carton number of a graph, defined to be the minimum size of a…

Combinatorics · Mathematics 2026-03-12 Seamus Connor , Steven DiSilvio , Sasha Kononova , Ralph Morrison , Krish Singal

We consider graph classes $\mathcal G$ in which every graph has components in a class $\mathcal{C}$ of connected graphs. We provide a framework for the asymptotic study of $\lvert\mathcal{G}_{n,N}\rvert$, the number of graphs in…

Combinatorics · Mathematics 2018-01-17 Konstantinos Panagiotou , Leon Ramzews

We study graph parameters whose associated edge-connection matrices have exponentially bounded rank growth. Our main result is an explicit construction of a large class of graph parameters with this property that we call mixed partition…

Combinatorics · Mathematics 2020-06-16 Guus Regts , Bart Sevenster

We investigate the behavior of the higher-order degrees, db_n, of a finitely presented group G. These db_n are functions from H^1(G;Z) to Z whose values are the degrees certain higher-order Alexander polynomials. We show that if def(G) is…

Geometric Topology · Mathematics 2009-11-11 Shelly L. Harvey

For a planar graph with a given f-vector $(f_{0}, f_{1}, f_{2}),$ we introduce a cubic polynomial whose coefficients depend on the f-vector. The planar graph is said to be real if all the roots of the corresponding polynomial are real. Thus…

Combinatorics · Mathematics 2018-03-29 M. R. Emamy-K. , Bahman Kalantari , Tatiana Correa

We generalize two main theorems of matching polynomials of undirected simple graphs, namely, real-rootedness and the Heilmann-Lieb root bound. Viewing the matching polynomial of a graph $G$ as the independence polynomial of the line graph…

Combinatorics · Mathematics 2019-02-20 Jonathan Leake , Nick Ryder

We identify a sufficient condition, treewidth-pliability, that gives a polynomial-time algorithm for an arbitrarily good approximation of the optimal value in a large class of Max-2-CSPs parameterised by the class of allowed constraint…

Discrete Mathematics · Computer Science 2024-01-04 Miguel Romero , Marcin Wrochna , Stanislav Živný

Random geometric graphs result from taking $n$ uniformly distributed points in the unit cube, $[0,1]^d$, and connecting two points if their Euclidean distance is at most $r$, for some prescribed $r$. We show that monotone properties for…

Probability · Mathematics 2007-05-23 Ashish Goel , Sanatan Rai , Bhaskar Krishnamachari

In this paper, we introduce a new concept namely degree polynomial for vertices of a simple graph. This notion leads to a concept namely degree polynomial sequence which is stronger than the concept of degree sequence. After obtaining the…

Combinatorics · Mathematics 2020-09-02 Reza Jafarpour-Golzari

Trivial links are unique up to number of link components, but they can be hard to recognize from arbitrary diagrams. We define a new measure of the complexity of a link embedding, the crumple, and show how this may be used to measure…

Geometric Topology · Mathematics 2013-02-28 Chad Musick

We establish relations between the bandwidth and the treewidth of bounded degree graphs G, and relate these parameters to the size of a separator of G as well as the size of an expanding subgraph of G. Our results imply that if one of these…

Combinatorics · Mathematics 2009-10-19 Julia Böttcher , Klaas P. Pruessmann , Anusch Taraz , Andreas Würfl

Let G = (V;E) be a simple graph. We consider domination polynomial, matching polynomial and edge cover polynomial of G. Graphs which their polynomials have few roots can give sometimes a very surprising information about the structure of…

Combinatorics · Mathematics 2011-12-06 Saeid Alikhani