On Ethnomathematics: In Memory of Ubiratan D'Ambrosio
The purpose of this note is to honour memory of Ubiratan D'Ambrosio, a Brazilian mathematics educator, who passed away on May 12, 2021.
math.HO↗
arXiv subjects
Veselin Jungic
Publications and source records attributed to Veselin Jungic.
A note on edge-colourings avoiding rainbow K_4 and monochromatic K_m
We study the mixed Ramsey number maxR(n,K_m,K_r), defined as the maximum number of colours in an edge-colouring of the complete graph K_n, such that K_n has no monochromatic complete subgraph on m vertices and no rainbow complete subgraph on r vertices. Improving an upper bound of Axenovich and Iverson, we show that maxR(n,K_m,K_4) <= n^{3/2}\sqrt{2m} for all m >= 3. Further, we discuss a possible way to improve their lower bound on maxR(n,K_4,K_4) based on incidence graphs of finite projective planes.
math.CO↗