T-Colorings, Divisibility and the Circular Chromatic Number

Abstract

Let T be a T -set, i.e., a finite set of nonnegative integers satisfying 0 ∈ T, and G be a graph. In the paper we study relations between the T -edge spans espT (G) and espd⊙T(G), where d is a positive integer and d⊙T={0≤t≤d(maxT+1):d|t⇒t/d∈T}.d \odot T = \left\{ {0 \le t \le d\left( {\max T + 1} \right):d|t \Rightarrow t/d \in T} \right\}.

Keywords

• t -coloring
• circular chromatic number
• 05c15