xx ( xxxx ) 1 – 14 2 ON THE STRONG PARITY CHROMATIC NUMBER

12 A vertex colouring of a 2-connected plane graph G is a strong parity 13 vertex colouring if for every face f and each colour c, the number of 14 vertices incident with f coloured by c is either zero or odd. 15 Czap et al. in [9] proved that every 2-connected plane graph has a 16 proper strong parity vertex colouring with at most 118 colours. 17 In this paper we improve this upper bound for some classes of plane 18 graphs. 19