Packing chromatic number versus chromatic and clique number

被引:11
作者
Bresar, Bostjan [1 ,2 ]
Klavzar, Sandi [1 ,2 ,3 ]
Rall, Douglas F. [4 ]
Wash, Kirsti [5 ]
机构
[1] Univ Maribor, Fac Nat Sci & Math, Maribor, Slovenia
[2] Inst Math Phys & Mech, Ljubljana, Slovenia
[3] Univ Ljubljana, Fac Math & Phys, Ljubljana, Slovenia
[4] Furman Univ, Dept Math, Greenville, SC 29613 USA
[5] Western New England Univ, Dept Math, Springfield, MA USA
关键词
Packing chromatic number; Chromatic number; Clique number; Independence number; Mycielskian; HEXAGONAL LATTICE; DISTANCE GRAPHS; COLORINGS; PRODUCT;
D O I
10.1007/s00010-017-0520-9
中图分类号
O29 [应用数学];
学科分类号
070104 ;
摘要
The packing chromatic number of a graph G is the smallest integer k such that the vertex set of G can be partitioned into sets , , where each is an i-packing. In this paper, we investigate for a given triple (a, b, c) of positive integers whether there exists a graph G such that , , and . If so, we say that (a, b, c) is realizable. It is proved that implies , and that triples and are not realizable as soon as . Some of the obtained results are deduced from the bounds proved on the packing chromatic number of the Mycielskian. Moreover, a formula for the independence number of the Mycielskian is given. A lower bound chi(rho)(G) on in terms of Delta(G) and alpha(G) is also proved.
引用
收藏
页码:497 / 513
页数:17
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