Turán Colourings in Off-Diagonal Ramsey Multiplicity

The Ramsey multiplicity constant of a graph $H$ is the limit as $n$ tends to infinity of the minimum density of monochromatic labeled copies of $H$ in a $2$-edge colouring of $K_n$. Fox and Wigderson recently identified a large family of graphs whose Ramsey multiplicity constants are attained by seq...

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Bibliographic Details
Published inThe Electronic journal of combinatorics Vol. 32; no. 2
Main Authors Hyde, Joseph, Lee, Jae-baek, Noel, Jonathan A.
Format Journal Article
LanguageEnglish
Published 25.04.2025
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Summary:The Ramsey multiplicity constant of a graph $H$ is the limit as $n$ tends to infinity of the minimum density of monochromatic labeled copies of $H$ in a $2$-edge colouring of $K_n$. Fox and Wigderson recently identified a large family of graphs whose Ramsey multiplicity constants are attained by sequences of "Turán colourings"; i.e. colourings in which one of the colour classes forms the edge set of a balanced complete multipartite graph. Each graph in their family comes from taking a connected non-3-colourable graph with a critical edge and adding many pendant edges. We extend their result to an off-diagonal variant of the Ramsey multiplicity constant which involves minimizing a weighted sum of red copies of one graph and blue copies of another.
ISSN:1077-8926
1077-8926
DOI:10.37236/12751