The typical structure of Gallai colorings and their extremal graphs

J Balogh, L Li - SIAM Journal on Discrete Mathematics, 2019 - SIAM
An edge coloring of a graph G is a Gallai coloring if it contains no rainbow triangle. We show
that the number of Gallai r-colorings of K_n is (r2+o(1))2^n2. This result indicates that almost …

[HTML][HTML] Edge-colorings of graphs avoiding complete graphs with a prescribed coloring

FS Benevides, C Hoppen, RM Sampaio - Discrete Mathematics, 2017 - Elsevier
Given a graph F and an integer r≥ 2, a partition F ̂ of the edge set of F into at most r
classes, and a graph G, define cr, F ̂ (G) as the number of r-colorings of the edges of G that …

[HTML][HTML] The number of Gallai k-colorings of complete graphs

J de Oliveira Bastos, FS Benevides, J Han - Journal of Combinatorial …, 2020 - Elsevier
An edge coloring of the n-vertex complete graph, K n, is a Gallai coloring if it does not
contain any rainbow triangle, that is, a triangle whose edges are colored with three distinct …

On the multicolor Tur\'{a} n conjecture for color-critical graphs

X Li, J Ma, Z Zheng - arXiv preprint arXiv:2407.14905, 2024 - arxiv.org
A {\it simple $ k $-coloring} of a multigraph $ G $ is a decomposition of the edge multiset as a
disjoint sum of $ k $ simple graphs which are referred as colors. A subgraph $ H $ of a …

A rainbow Erdös--Rothschild problem

C Hoppen, H Lefmann, K Odermann - SIAM Journal on Discrete Mathematics, 2017 - SIAM
We consider a multicolored version of a question posed by Erdös and Rothschild. For a
fixed positive integer r and a fixed graph F, we look for n-vertex graphs that admit the …

[HTML][HTML] On graphs with a large number of edge-colorings avoiding a rainbow triangle

C Hoppen, H Lefmann, K Odermann - European Journal of Combinatorics, 2017 - Elsevier
Inspired by previous work of Balogh (2006), we show that, given r≥ 5 and n large, the
balanced complete bipartite graph K n∕ 2, n∕ 2 is the n-vertex graph that admits the largest …

[HTML][HTML] Counting Gallai 3-colorings of complete graphs

J de Oliveira Bastos, FS Benevides, GO Mota, I Sau - Discrete Mathematics, 2019 - Elsevier
An edge coloring of the n-vertex complete graph K n is a Gallai coloring if it does not contain
any rainbow triangle, that is, a triangle whose edges are colored with three distinct colors …

Edge-colorings avoiding patterns in a triangle

C Hoppen, H Lefmann, DR Schmidt - Discrete Mathematics, 2024 - Elsevier
For positive integers n and r, we consider n-vertex graphs with the maximum number of r-
edge-colorings with no copy of a triangle where exactly two colors appear. We prove that, if …

An extension of the rainbow Erdős-Rothschild problem

C Hoppen, H Lefmann, D Nolibos - Discrete Mathematics, 2021 - Elsevier
Given integers r≥ 2, k≥ 3 and 2≤ s≤(k 2), and a graph G, we consider r-edge-colorings of
G with no copy of a complete graph K k on k vertices where s or more colors appear, which …

Graphs with many edge-colorings such that complete graphs are rainbow

JO Bastos, C Hoppen, H Lefmann, A Oertel… - Discrete Applied …, 2023 - Elsevier
We consider a version of the Erdős–Rothschild problem for families of graph patterns. For
any fixed k≥ 3, let r 0 (k) be the largest integer such that the following holds for all 2≤ r≤ r 0 …