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We determine the maximum possible number of edges of a graph with $n$ vertices, matching number at most $s$ and clique number at most $k$ for all admissible values of the parameters.

Combinatorics · Mathematics 2022-10-28 Noga Alon , Peter Frankl

We study triangle decompositions of graphs. We consider constructions of classes of graphs where every edge lies on a triangle and the addition of the minimum number of multiple edges between already adjacent vertices results in a strongly…

Combinatorics · Mathematics 2021-08-23 C. M. Mynhardt , A. K. Wright

We show that a matchstick graph with $n$ vertices has no more than $3n-c\sqrt{n-1/4}$ edges, where $c=\frac12(\sqrt{12} + \sqrt{2\pi\sqrt{3}})$. The main tools in the proof are the Euler formula, the isoperimetric inequality, and an upper…

Combinatorics · Mathematics 2021-08-18 Jérémy Lavollée , Konrad J. Swanepoel

A famous conjecture of Tuza \cite{tuza} is that the minimal number of edges needed to cover all triangles in a graph is at most twice the maximal number of edge-disjoint triangles. We propose a wider setting for this conjecture. For a…

Combinatorics · Mathematics 2019-12-19 Ron Aharoni , Shira Zerbib

A well-known conjecture by Erd\H{o}s states that every triangle-free graph on $n$ vertices can be made bipartite by removing at most $n^2/25$ edges. This conjecture was known for graphs with edge density at least $0.4$ and edge density at…

Combinatorics · Mathematics 2021-03-29 József Balogh , Felix Christian Clemen , Bernard Lidický

Extremal problems concerning the number of independent sets or complete subgraphs in a graph have been well studied in recent years. Cutler and Radcliffe proved that among graphs with $n$ vertices and maximum degree at most $r$, where $n =…

Combinatorics · Mathematics 2019-06-11 R. Kirsch , A. J. Radcliffe

We prove that, for sufficiently large $n$, every graph of order $n$ with minimum degree at least $0.852n$ has a fractional edge-decomposition into triangles. We do this by refining a method used by Dross to establish a bound of $0.9n$. By a…

Combinatorics · Mathematics 2020-01-17 Peter J. Dukes , Daniel Horsley

One of the earliest results in extremal graph theory, Mantel's theorem, states that the maximum number of edges in a triangle-free graph $G$ on $n$ vertices is $\lfloor n^2/4 \rfloor$. We investigate how this extremal bound is affected when…

Combinatorics · Mathematics 2025-07-01 Natalie Behague , Debsoumya Chakraborti , Xizhi Liu

In this thesis we consider ordered graphs (that is, graphs with a fixed linear ordering on their vertices). We summarize and further investigations on the number of edges an ordered graph may have while avoiding a fixed forbidden ordered…

Discrete Mathematics · Computer Science 2009-07-16 Craig Weidert

We consider the problem of covering a graph with a given number of induced subgraphs so that the maximum number of vertices in each subgraph is minimized. We prove NP-completeness of the problem, prove lower bounds, and give approximation…

Discrete Mathematics · Computer Science 2007-05-23 Shripad Thite

The widely studied edge modification problems ask how to minimally alter a graph to satisfy certain structural properties. In this paper, we introduce and study a new edge modification problem centered around transforming a given graph into…

Data Structures and Algorithms · Computer Science 2025-09-16 Amirali Madani , Anil Maheshwari , Babak Miraftab , Paweł Żyliński

A triangle decomposition of a graph is a partition of its edges into triangles. A fractional triangle decomposition of a graph is an assignment of a non-negative weight to each of its triangles such that the sum of the weights of the…

Combinatorics · Mathematics 2015-07-22 François Dross

We introduce a variant of the vertex-distinguishing edge coloring problem, where each edge is assigned a subset of colors. The label of a vertex is the union of the sets of colors on edges incident to it. In this paper we investigate the…

Discrete Mathematics · Computer Science 2026-04-17 Nicolas Bousquet , Antoine Dailly , Eric Duchene , Hamamache Kheddouci , Aline Parreau

In this paper, we study two examples of minimum weight random graphs with edge constraints. First we consider the complete graph on ${n}$ vertices equipped with uniformly heavy edge weights and use iteration methods to obtain deviation…

Probability · Mathematics 2023-01-13 Ghurumuruhan Ganesan

In 1959, Goodman determined the minimum number of monochromatic triangles in a complete graph whose edge set is two-coloured. Goodman also raised the question of proving analogous results for complete graphs whose edge sets are coloured…

Combinatorics · Mathematics 2012-06-12 James Cummings , Daniel Král' , Florian Pfender , Konrad Sperfeld , Andrew Treglown , Michael Young

We consider the problem of minimizing the number of triangles in a graph of given order and size and describe the asymptotic structure of extremal graphs. This is achieved by characterizing the set of flag algebra homomorphisms that…

Combinatorics · Mathematics 2016-05-11 Oleg Pikhurko , Alexander Razborov

We describe a new algorithm to compute the geometric intersection number between two curves, given as edge vectors on an ideal triangulation. Most importantly, this algorithm runs in polynomial time in the bit-size of the two edge vectors.…

Geometric Topology · Mathematics 2016-05-12 Mark C. Bell , Richard C. H. Webb

A convex geometric graph is a graph whose vertices are the corners of a convex polygon P in the plane and whose edges are boundary edges and diagonals of the polygon. It is called triangulation-free if its non-boundary edges do not contain…

Combinatorics · Mathematics 2025-08-19 David Garber , Chaya Keller , Olga Nissenbaum , Shimon Aviram

A celebrated conjecture of Zs. Tuza says that in any (finite) graph, the minimum size of a cover of triangles by edges is at most twice the maximum size of a set of edge-disjoint triangles. Resolving a recent question of Bennett, Dudek, and…

Combinatorics · Mathematics 2020-07-13 Jeff Kahn , Jinyoung Park

We give a sharp bound on the number of triangles in a graph with fixed number of edges. We also characterize graphs that achieve the maximum number of triangles. Using the upper bound on number of triangles, we prove that if $G$ is a…

Group Theory · Mathematics 2022-05-13 Tony N. Mavely , Viji Z. Thomas