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Neighbor Sum Distinguishing Total Coloring Of Planar Graphs With Cycle Conditions

Posted on:2020-12-11Degree:MasterType:Thesis
Country:ChinaCandidate:X ZhaoFull Text:PDF
GTID:2480306563967299Subject:Mathematics
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Let graph G be undirected,finite and simple.If any two incident or adjacent vertices and edges of G receive different colors denoted by natural number,then such a coloring is a proper total coloring of graph G.Furthermore,for any adjacent vertices u and v,if the sum of colors of vertex u and edges incident with u is different from the sum of colors of vertex v and edges incident with v.then such a coloring is a neighbor sum distinguishing total coloring of graph G.The smallest value of the number of colors needed in such a coloring of G is called the neighbor sum distinguishing total chromatic number ?"?(G).In 2015,for neighbor sum distinguishing total chromatic number of graph G,Pilsniak and Wozniak conjectured that for any simple graph with maxi-mum degree ?(G),?"?(G)??(G)+3.By using Combinatorial Nullstellen-satz and discharging method,we study the neighbor sum distinguishing to-tal coloring of planar graphs without 5-cycles and without 6-cycles,and get the following conclusions:1.Let G be a planar graph without 5-cycles,then?"?(G)?max{?(G)+2,10};2.Let G be a planar graph without 5-cycles and maximum degree at least is 9.If G has no adjacent ?(G)-vertices,then?"?(G)=?(G)+1,otherwise ?"?(G)=?(G)+2;3.Let G be a planar graph without 6-cycles,then ?"?(G)?max{?(G)+3,10}.Conclusions 1 and Con-clusions 2 mean Pilsniak and Wozniak's conjecture is true for planar graph G without 5-cycles.At the same time,the bound of neighbor sum distinguishing total chromatic number is sharp.Conclusions 3 means Pilsniak and Wozniak's conjecture is true for planar graph G without 6-cycles.
Keywords/Search Tags:Planar graph, Discharging method, Neighbor sum distinguishing total coloring, Euler's Formula
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