Parity vertex colouring of plane graphs

A proper vertex colouring of a 2-connected plane graph GG is a parity vertex colouring   if for each face ff and each colour cc, either no vertex or an odd number of vertices incident with ff is coloured with cc. The minimum number of colours used in such a colouring of GG is denoted by χp(G)χp(G).In this paper, we prove that χp(G)≤118χp(G)≤118 for every 2-connected plane graph GG.