2018/12/17 by Simonyi, Gábor
#05C55 #Combinatorics (math.CO) #FOS: Mathematics
paper · doi:10.48550/arxiv.1812.06706
An edge-coloring of the complete graph Kn we call F-caring if it leaves no F-subgraph of Kn monochromatic and at the same time every subset of |V(F)| vertices contains in it at least one completely multicolored version of F. For the first two meaningful cases, when F=K1,3 and F=P4 we determine for infinitely many n the minimum number of colors needed for an F-caring edge-coloring of Kn. An explicit family of 2\lceillog2 n\rceil 3-edge-colorings of Kn so that every quadruple of its vertices contains a totally multicolored P4 in at least one of them is also presented. Investigating related Ramsey-type problems we also show that the Shannon (OR-)capacity of the Grötzsch graph is strictly larger than that of the five length cycle.