Note: Dynamic coloring and list dynamic coloring of planar graphs

  • Authors:
  • Seog-Jin Kim;Sang June Lee;Won-Jin Park

  • Affiliations:
  • -;-;-

  • Venue:
  • Discrete Applied Mathematics
  • Year:
  • 2013

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Abstract

A dynamic coloring of a graph G is a proper coloring of the vertex set V(G) such that for each vertex of degree at least 2, its neighbors receive at least two distinct colors. The dynamic chromatic number@g"d(G) of a graph G is the least number k such that G has a dynamic coloring with k colors. We show that @g"d(G)@?4 for every planar graph except C"5, which was conjectured in Chen et al. (2012) [5]. The list dynamic chromatic numberch"d(G) of G is the least number k such that for any assignment of k-element lists to the vertices of G, there is a dynamic coloring of G where the color on each vertex is chosen from its list. Based on Thomassen's (1994) result [14] that every planar graph is 5-choosable, an interesting question is whether the list dynamic chromatic number of every planar graph is at most 5 or not. We answer this question by showing that ch"d(G)@?5 for every planar graph.