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A univariate graph polynomial P(G;X) is weakly distinguishing if for almost all finite graphs G there is a finite graph H with P(G;X)=P(H;X). We show that the clique polynomial and the independence polynomial are weakly distinguishing.…

Combinatorics · Mathematics 2023-06-22 Johann A. Makowsky , Vsevolod Rakita

For a graph $G=(V,E)$, a subset $D$ of vertex set $V$, is a dominating set of $G$ if every vertex not in $D$ is adjacent to atleast one vertex of $D$. A dominating set $D$ of a graph $G$ with no isolated vertices is called a paired…

Discrete Mathematics · Computer Science 2021-12-13 Vikash Tripathi , Ton Kloks , Arti Pandey , Kaustav Paul , Hung-Lung Wang

A mapping $\alpha : V(G) \to V(H)$ from the vertex set of one graph $G$ to another graph $H$ is an isometric embedding if the shortest path distance between any two vertices in $G$ equals the distance between their images in $H$. Here, we…

Discrete Mathematics · Computer Science 2021-12-21 Joseph Berleant , Kristin Sheridan , Anne Condon , Virginia Vassilevska Williams , Mark Bathe

A graph is called $P_t$-free} if it does not contain a $t$-vertex path as an induced subgraph. While $P_4$-free graphs are exactly cographs, the structure of $P_t$-free graphs for $t \geq 5$ remains little understood. On one hand, classic…

Discrete Mathematics · Computer Science 2020-03-30 Andrzej Grzesik , Tereza Klimošová , Marcin Pilipczuk , Michał Pilipczuk

Given an $n$-vertex pseudorandom graph $G$ and an $n$-vertex graph $H$ with maximum degree at most two, we wish to find a copy of $H$ in $G$, i.e.\ an embedding $\varphi\colon V(H)\to V(G)$ so that $\varphi(u)\varphi(v)\in E(G)$ for all…

Combinatorics · Mathematics 2023-04-06 Jie Han , Yoshiharu Kohayakawa , Patrick Morris , Yury Person

We study graphs of polynomial growth from the perspective of asymptotic geometry and descriptive set theory. The starting point of our investigation is a theorem of Krauthgamer and Lee who showed that every connected graph of polynomial…

Combinatorics · Mathematics 2025-04-08 Anton Bernshteyn , Jing Yu

Approximating the partition function of the ferromagnetic Ising model with general external fields is known to be #BIS-hard in the worst case, even for bounded-degree graphs, and it is widely believed that no polynomial-time approximation…

Data Structures and Algorithms · Computer Science 2021-08-27 Tyler Helmuth , Holden Lee , Will Perkins , Mohan Ravichandran , Qiang Wu

An identifying code of a graph is a subset of its vertices such that every vertex of the graph is uniquely identified by the set of its neighbours within the code. We show a dichotomy for the size of the smallest identifying code in classes…

Discrete Mathematics · Computer Science 2017-04-17 Nicolas Bousquet , Aurélie Lagoutte , Zhentao Li , Aline Parreau , Stéphan Thomassé

Paths P1,...,Pk in a graph G=(V,E) are said to be mutually induced if for any 1 <= i < j <= k, Pi and Pj have neither common vertices nor adjacent vertices (except perhaps their end-vertices). The Induced Disjoint Paths problem is to test…

Discrete Mathematics · Computer Science 2014-03-07 Petr A. Golovach , Daniel Paulusma , Erik Jan van Leeuwen

A graph $G$ is $H$-induced-saturated if $G$ is $H$-free but deleting any edge or adding any edge creates an induced copy of $H$. There are non-trivial graphs $H$, such as $P_4$, for which no finite $H$-induced-saturated graph $G$ exists. We…

Combinatorics · Mathematics 2025-09-03 Marthe Bonamy , Carla Groenland , Tom Johnston , Natasha Morrison , Alex Scott

A homomorphism from a graph $G$ to a graph $H$ is an edge-preserving mapping from $V(G)$ to $V(H)$. For a fixed graph $H$, in the list homomorphism problem, denoted by LHom($H$), we are given a graph $G$, whose every vertex $v$ is equipped…

Computational Complexity · Computer Science 2022-02-04 Karolina Okrasa , Paweł Rzążewski

The bidimensionality of a set of vertices $X$ in a graph $G$ is the maximum $k$ for which $G$ contains as a $X$-rooted minor the $(k \times k)$-grid. This notion allows for the following version of the Graph Minors Structure Theorem (GMST)…

Combinatorics · Mathematics 2026-05-27 Dimitrios M. Thilikos , Sebastian Wiederrecht

We prove that for every path $P$, the class of graphs with no induced $P$ and no induced four-cycle $C_4$ is linearly $\chi$-bounded. More generally, we ask for which pairs $\{T,H\}$ where $T$ is a forest and $H$ is a complete multipartite…

Combinatorics · Mathematics 2026-05-12 Tung Nguyen , Sang-il Oum

We study the computational complexity of several problems connected with finding a maximal distance-$k$ matching of minimum cardinality or minimum weight in a given graph. We introduce the class of $k$-equimatchable graphs which is an edge…

Discrete Mathematics · Computer Science 2024-11-19 Yury Kartynnik , Andrew Ryzhikov

Let H be a graph, and let C_H(G) be the number of (subgraph isomorphic) copies of H contained in a graph G. We investigate the fundamental problem of estimating C_H(G). Previous results cover only a few specific instances of this general…

Data Structures and Algorithms · Computer Science 2019-02-20 Martin Furer , Shiva Prasad Kasiviswanathan

In a finite undirected graph $G=(V,E)$, a vertex $v \in V$ {\em dominates} itself and its neighbors in $G$. A vertex set $D \subseteq V$ is an {\em efficient dominating set} ({\em e.d.} for short) of $G$ if every $v \in V$ is dominated in…

Discrete Mathematics · Computer Science 2015-09-15 Andreas Brandstadt , Raffaele Mosca

A graph polynomial $P$ is weakly distinguishing if for almost all finite graphs $G$ there is a finite graph $H$ that is not isomorphic to $G$ with $P(G)=P(H)$. It is weakly distinguishing on a graph property $\mathcal{C}$ if for almost all…

Combinatorics · Mathematics 2020-10-21 Johann A. Makowsky , Vsevolod Rakita

In a graph $G = (V,E)$, a k-ruling set $S$ is one in which all vertices $V$ \ $S$ are at most $k$ distance from $S$. Finding a minimum k-ruling set is intrinsically linked to the minimum dominating set problem and maximal independent set…

Data Structures and Algorithms · Computer Science 2024-09-27 Max Koster

The question to enumerate all inclusion-minimal connected dominating sets in a graph of order $n$ in time significantly less than $2^n$ is an open question that was asked in many places. We answer this question affirmatively, by providing…

Computational Complexity · Computer Science 2022-05-03 Faisal Abu-Khzam , Henning Fernau , Benjamin Gras , Mathieu Liedloff , Kevin Mann

For unweighted graphs, finding isometric embeddings is closely related to decompositions of $G$ into Cartesian products of smaller graphs. When $G$ is isomorphic to a Cartesian graph product, we call the factors of this product a…

Data Structures and Algorithms · Computer Science 2021-12-15 Kristin Sheridan , Joseph Berleant , Mark Bathe , Anne Condon , Virginia Vassilevska Williams