3 research outputs found
Extremal problems and results related to Gallai-colorings
A Gallai-coloring (Gallai--coloring) is an edge-coloring (with colors from
) of a complete graph without rainbow triangles. Given a
graph and a positive integer , the -colored Gallai-Ramsey number
is the minimum integer such that every Gallai--coloring of the
complete graph contains a monochromatic copy of . In this paper, we
prove that for any positive integers and , there exists a constant
such that if is an -vertex graph with maximum degree , then
is at most . We also determine for the graph on 5 vertices
consisting of a with a pendant edge. Furthermore, we consider two
extremal problems related to Gallai--colorings. For , we
determine upper and lower bounds for the minimum number of monochromatic
triangles in a Gallai--coloring of , implying that this number is
and yielding the exact value for . We also determine upper and
lower bounds for the maximum number of edges that are not contained in any
rainbow triangle or monochromatic triangle in a -edge-coloring of .Comment: 20 pages, 1 figur