图G的一个正常[k]-全染色是一个映射Φ:V∪E→{1,2,…,k},使得V∪E中任意一对相邻或者相关联元素染不同颜色。用f(v)表示点v及所有与其关联的边的颜色的加和,若对任意uv∈E(G),有f(u)≠f(v),则称该染色为图G的[k]-邻和可区别全染色。k的最小值称作图G的邻和可区别全色数,记为tndiΣ(G)。Pils'niak和Woz'niak提出猜想:对任意简单图G,有tndiΣ(G)≤Δ(G)+3,其中Δ(G)为图G的最大度。图G的最大平均度,记为mad(G),是G的所有非空子图的平均度的最大值。运用组合零点定理和权转移方法,证明了若Δ(G)=3且mad(G)〈12/5,或Δ(G)=4且mad(G)〈5/2,则tndiΣ(G)≤Δ(G)+2。
A proper [k]-total coloring of a graph G is a map Φ: V∪E→{ 1,2,…,k} such that Φ( x) ≠Φ( y) for each pair of adjacent or incident elements x,y∈V∪E. Let f( v) denote the sum of the color of vertex v and the colors of the edges incident with v. A [k]-neighbor sum distinguishing total coloring of G is a [k]-total coloring of G such that for each edge uv∈E( G),f( u) ≠f( v). Let tndiΣ( G) denote the smallest value k in such a coloring of G. Pils' niak and Woz'niak first introduced this coloring and conjectured that tndiΣ( G) ≤Δ( G) + 3 for any simple graph with maximum degree Δ( G). The maximum average degree of G is the maximum of the average degree of its non-empty subgraphs,which is denoted by mad( G). By using the Combinatorial Nullstellensatz and the discharging method,it is proved that if G is a graph with Δ( G) = 3 and mad( G) 12/5,or Δ( G) = 4 and mad( G) 52,then tndiΣ( G) ≤Δ( G) + 2.