On Two Problems about \((0,2)\)-Graphs and Interval-Regular Graphs

Abdelhafid Berrachedi1, Michel Mollard2
1 Insitut de mathématiques, USTHB BP 32 El Alia 16111 Alger, Algérie
2LSD2(IMAG) BP 53 38041 Grenoble CEDEX 9 France

Abstract

We give operations on graphs preserving the property of being a \((0,2)\)-graph. In particular, these operations allow the construction of non-vertex-transitive \((0,2)\)-graphs. We also construct a family of regular interval-regular graphs which are not interval monotone, thus disproving a weaker version of a conjecture proposed by H.M. Mulder.