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In this paper, we investigate the problem of covering the vertices of a graph associated to a finite vector space as introduced by Das \cite{Das}, such that we can uniquely identify any vertex by examining the vertices that cover it. We use…

Combinatorics · Mathematics 2017-01-31 Muhammad Murtaza , Imran Javaid , Muhammad Fazil

We establish two versions of Vizing's theorem for Borel multi-graphs whose vertex degrees and edge multiplicities are uniformly bounded by respectively $\Delta$ and $\pi$. The ``approximate'' version states that, for any Borel probability…

Combinatorics · Mathematics 2020-07-21 Jan Grebík , Oleg Pikhurko

In 1981, Tuza conjectured that the cardinality of a minimum set of edges that intersects every triangle of a graph is at most twice the cardinality of a maximum set of edge-disjoint triangles. This conjecture have been proved for several…

Combinatorics · Mathematics 2023-07-20 Luis Chahua , Juan Gutiérrez

A set $S\subseteq V$ is a dominating set of $G$ if every vertex in $V - S$ is adjacent to at least one vertex in $S$. The domination number $\gamma(G)$ of $G$ equals the minimum cardinality of a dominating set $S$ in $G$; we say that such a…

Combinatorics · Mathematics 2017-05-10 Benjamin M. Case , Stephen T. Hedetniemi , Renu C. Laskar , Drew J. Lipman

The P versus NP problem asks whether every language verifiable in polynomial time can also be decided in deterministic polynomial time. In this paper, we present a constructive proof that P = NP by introducing a universal, graph-based…

Computational Complexity · Computer Science 2026-04-02 Changryeol Lee

For an $n$-vertex graph $G$, let $z(G;k)$ denote the number of zero forcing sets of size $k$. A conjecture of Boyer et al. asserts that the path $P_n$ maximizes these numbers coefficientwise among all $n$-vertex graphs; equivalently, the…

Discrete Mathematics · Computer Science 2026-05-12 Samuel German

A numerical semigroup $S$ is an additively-closed set of non-negative integers, and a factorization of an element $n$ of $S$ is an expression of $n$ as a sum of generators of $S$. It is known that for a given numerical semigroup $S$, the…

Combinatorics · Mathematics 2025-11-19 Mariah Moschetti , Christopher O'Neill

Let $\mathbb{Q}$ (resp. $\mathbb{R}$) be the field of rational (resp. real) numbers and $X = (X_1, \ldots, X_n)$ be variables. Deciding the non-negativity of polynomials in $\mathbb{Q}[X]$ over $\mathbb{R}^n$ or over semi-algebraic domains…

Symbolic Computation · Computer Science 2018-05-08 Victor Magron , Mohab Safey El Din

Let $G=(V,E)$ be a graph without isolated vertices. A set $S\subseteq V$ is a paired-domination set if every vertex in $V-S$ is adjacent to a vertex in $S$ and the subgraph induced by $S$ contains a perfect matching. The paired-domination…

Combinatorics · Mathematics 2008-02-21 Lei Chen Changhong Lu Zhenbing Zeng

Amoebas and coamoebas are the logarithmic images of algebraic varieties and the images of algebraic varieties under the arg-map, respectively. We present new techniques for computational problems on amoebas and coamoebas, thus establishing…

Algebraic Geometry · Mathematics 2013-06-14 Thorsten Theobald , Timo de Wolff

In this paper we consider the problem of how to computationally test whether a matrix inequality is positive semidefinite on a semialgebraic set. We propose a family of sufficient conditions using the theory of matrix Positivstellensatz…

Optimization and Control · Mathematics 2007-05-23 Been-Der Chen , Sanjay Lall

Recently the notion of $k$-rainbow total domination was introduced for a graph $G$, motivated by a desire to reduce the problem of computing the total domination number of the generalized prism $G \Box K_k$ to an integer labeling problem on…

Combinatorics · Mathematics 2020-03-24 Kerry Ojakian , Riste Skrekovski , Aleksandra Tepeh

Let $G$ be a simple graph of order $n$. The domination polynomial of $G$ is the polynomial $D(G, x)=\sum_{i=1}^n d(G,i) x^i$, where $d(G,i)$ is the number of dominating sets of $G$ of size $i$. For two graphs $G$ and $H$, let $\mathcal{C} =…

Combinatorics · Mathematics 2016-05-10 Somayeh Jahari , Saeid Alikhani

A graph $H$ is said to be positive if the homomorphism density $t_H(G)$ is non-negative for all weighted graphs $G$. The positive graph conjecture proposes a characterisation of such graphs, saying that a graph is positive if and only if it…

Combinatorics · Mathematics 2024-04-29 David Conlon , Joonkyung Lee , Leo Versteegen

The dominating graph of a graph G is a graph whose vertices correspond to the dominating sets of G and two vertices are adjacent whenever their corresponding dominating sets differ in exactly one vertex. Studying properties of dominating…

Combinatorics · Mathematics 2022-12-12 Alireza Mofidi

Positivstellensatz is a fundamental result in real algebraic geometry providing algebraic certificates for positivity of polynomials on semialgebraic sets. In this article Positivstellens\"atze for trace polynomials positive on…

Rings and Algebras · Mathematics 2019-01-23 Igor Klep , Špela Špenko , Jurij Volčič

We consider real polynomials in finitely many variables. Let the variables consist of finitely many blocks that are allowed to overlap in a certain way. Let the solution set of a finite system of polynomial inequalities be given where each…

Optimization and Control · Mathematics 2007-05-23 David Grimm , Tim Netzer , Markus Schweighofer

There is a profound connection between copositive matrices and graph theory. Copositive matrices provide a powerful tool for formulating and solving various challenging graph-related problems. Conversely, graph theory provides a rich set of…

Optimization and Control · Mathematics 2024-10-11 O. I. Kostyukova , T. V. Tchemisova

An identifying code in a graph $G$ is a dominating set $C$ such that the closed neighborhood of each vertex in $G$ has a distinct intersection with $C$. In 2008, Gravier et al. determined the minimum cardinality of an identifying code of…

Combinatorics · Mathematics 2014-12-09 Yingnan Zhang , Min Feng , Kaishun Wang

Fuzzy incidence graphs (FIG) model real world problems efficiently when there is an extra attribute of vertex-edge relationship. The article discusses the operations on Fuzzy incidence graphs. The join, Cartesian product, tensor product,…

Combinatorics · Mathematics 2022-10-26 Kavya. R. Nair , M. S. Sunitha
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