ISSN 1234-3099 (print version)

ISSN 2083-5892 (electronic version)

Discussiones Mathematicae Graph Theory

IMPACT FACTOR 2018: 0.741

SCImago Journal Rank (SJR) 2018: 0.763

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Discussiones Mathematicae Graph Theory


Discussiones Mathematicae Graph Theory 16(2) (1996) 173-179
DOI: 10.7151/dmgt.1032


Sebastian Urbański

Department of Discrete Mathematics
Faculty of Mathematics and Computer Science
Adam Mickiewicz University Poznań, Poland


The paper gives an account of previous and recent attempts to determine the order of a smallest graph not containing K5 and such that every 2-coloring of its edges results in a monochromatic triangle. A new 14-vertex K4-free graph with the same Ramsey property in the vertex coloring case is found. This yields a new construction of one of the only two known 15-vertex (3,3)-Ramsey graphs not containing K5.

Keywords: Folkman numbers, Kn-free graphs, extremal graph theory, generalized Ramsey theory.

1991 Mathematics Subject Classification: 05C55, 05C35.


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