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Given a sequence $\mathbf{k} := (k_1,\ldots,k_s)$ of natural numbers and a graph $G$, let $F(G;\mathbf{k})$ denote the number of colourings of the edges of $G$ with colours $1,\dots,s$ such that, for every $c \in \{1,\dots,s\}$, the edges…

Combinatorics · Mathematics 2023-05-09 Oleg Pikhurko , Katherine Staden

The conjecture of Bollob\'as and Koml\'os, recently proved by B\"ottcher, Schacht, and Taraz [Math. Ann. 343(1), 175--205, 2009], implies that for any $\gamma>0$, every balanced bipartite graph on $2n$ vertices with bounded degree and…

Combinatorics · Mathematics 2011-07-28 Julia Böttcher , Peter Christian Heinig , Anusch Taraz

In the last decade, copositive formulations have been proposed for a variety of combinatorial optimization problems, for example the stability number (independence number). In this paper, we generalize this approach to infinite graphs and…

Optimization and Control · Mathematics 2016-10-12 Cristian Dobre , Mirjam Dür , Leonhard Frerick , Frank Vallentin

This survey paper deals with upper and lower bounds on the number of $k$-matchings in regular graphs on $N$ vertices. For the upper bounds we recall the upper matching conjecture which is known to hold for perfect matchings. For the lower…

Combinatorics · Mathematics 2012-01-06 Shmuel Friedland

This paper gives two different proofs to a structural theorem of decreasing minimization (lexicographic optimization) on integrally convex sets. The theorem states that the set of decreasingly minimal elements of an integrally convex set…

Optimization and Control · Mathematics 2025-04-28 Kazuo Murota , Akihisa Tamura

The vertex set of the Kneser graph $K(n,k)$ is $V = \binom{[n]}{k}$ and two vertices are adjacent if the corresponding sets are disjoint. For any graph $F$, the largest size of a vertex set $U \subseteq V$ such that $K(n,k)[U]$ is $F$-free,…

Combinatorics · Mathematics 2019-03-08 Dániel Gerbner , Abhishek Methuku , Dániel Nagy , Balázs Patkós , Máté Vizer

We develop a general theory of local stability up to belonging to an ideal (e.g. having measure zero). From a model-theoretic perspective, we prove a stationarity principle for almost stable formulas in this sense, and build a topological…

Logic · Mathematics 2025-08-04 Marcos Girón

Max-stable random sketches can be computed efficiently on fast streaming positive data sets by using only sequential access to the data. They can be used to answer point and Lp-norm queries for the signal. There is an intriguing connection…

Data Structures and Algorithms · Computer Science 2010-05-25 Stilian A. Stoev , Murad S. Taqqu

The stability number of a graph G, denoted by alpha(G), is the cardinality of a stable set of maximum size in G. If alpha(G-e) > alpha(G), then e is an alpha-critical edge, and if mu(G-e) < mu(G), then e is a mu-critical edge, where mu(G)…

Combinatorics · Mathematics 2007-05-23 Vadim E. Levit , Eugen Mandrescu

Given a digraph D, the minimum semi-degree of D is the minimum of its minimum indegree and its minimum outdegree. D is k-ordered Hamiltonian if for every ordered sequence of k distinct vertices there is a directed Hamilton cycle which…

Combinatorics · Mathematics 2007-07-12 Daniela Kühn , Deryk Osthus , Andrew Young

A subset $D\subseteq V(G)$ is called a $k$-distance dominating set of $G$ if every vertex in $V(G)\setminus D$ is within distance $k$ from some vertex of $D$. The minimum cardinality among all $k$-distance dominating sets of $G$ is called…

Combinatorics · Mathematics 2018-05-04 D. A. Mojdeh , S. R. Musawi , E. Nazari

The stability number of a graph G, denoted by alpha(G), is the cardinality of a maximum stable set, and mu(G) is the cardinality of a maximum matching in G. If alpha(G)+mu(G) equals its order, then G is a Konig-Egervary graph. In this paper…

Combinatorics · Mathematics 2011-01-25 Vadim E. Levit , Eugen Mandrescu

Given a digraph $D=(V,A)$, a set $B\subset V$ is a packing set in $D$ if there are no arcs joining vertices of $B$ and for any two vertices $x,y\in B$ the sets of in-neighbors of $x$ and $y$ are disjoint. The set $S$ is a dominating set (an…

Combinatorics · Mathematics 2021-08-25 Doost Ali Mojdeh , Babak Samadi , Ismael G. Yero

It was conjectured by Mkrtchyan, Petrosyan, and Vardanyan that every graph $G$ with $\Delta(G)-\delta(G) \le 1$ has a maximum matching $M$ such that any two $M$-unsaturated vertices do not share a neighbor. In this note, we confirm the…

Combinatorics · Mathematics 2016-11-22 Dong Ye

This chapter investigates the cone of copositive matrices, with a focus on the design and analysis of conic inner approximations for it. These approximations are based on various sufficient conditions for matrix copositivity, relying on…

Optimization and Control · Mathematics 2023-03-21 Luis Felipe Vargas , Monique Laurent

The classical Kruskal-Katona theorem gives a tight upper bound for the size of an $r$-uniform hypergraph $\mathcal{H}$ as a function of the size of its shadow. Its stability version was obtained by Keevash who proved that if the size of…

Combinatorics · Mathematics 2021-04-06 Xizhi Liu , Sayan Mukherjee

This replacement corrects statement and proof of the main result. Also, a section on the universal Abel-Jacobi map has been added.

alg-geom · Mathematics 2008-02-03 Eduard Looijenga

We compute for reflection groups of type $A,B,D,F_4,H_3$ and for dihedral groups a statistic counting the maximal cardinality of a set of elements in the group whose generalized inversions yield the full set of inversions and which are…

Representation Theory · Mathematics 2016-02-16 Claudia Malvenuto , Pierluigi Möseneder Frajria , Luigi Orsina , Paolo Papi

This paper unifies the theory of consistent-set maximization for robust outlier detection in a simultaneous localization and mapping framework. We first describe the notion of pairwise consistency before discussing how a consistency graph…

Robotics · Computer Science 2023-08-08 Brendon Forsgren , Ram Vasudevan , Michael Kaess , Timothy W. McLain , Joshua G. Mangelson

The $\Delta$-edge stability number ${\rm es}_{\Delta}(G)$ of a graph $G$ is the minimum number of edges of $G$ whose removal results in a subgraph $H$ with $\Delta(H) = \Delta(G)-1$. Sets whose removal results in a subgraph with smaller…