On the strong parity chromatic number
Július Czap, Stanislav Jendrol′, František Kardoš · Discussiones Mathematicae Graph Theory · 2011
A vertex colouring of a 2-connected plane graph G is a strong parity vertex colouring if for every face f and each colour c, the number of vertices incident with f coloured by c is either zero or odd.Czap et al. in [9] proved that every 2-connected plane graph has a proper strong parity vertex colouring with at most 118 colours.In this paper we improve this upper bound for some classes of plane graphs.