Further results on the j-independence number of graphs

Document Type : Original paper

Authors

LAMDA-RO Laboratory, Department of Mathematics, University of Blida, B.P. 270, Blida, Algeria

Abstract

In a graph G of minimum degree δ and maximum degree Δ, a subset S of vertices of G is j-independent, for some positive integer j, if every vertex in S has at most j1 neighbors in S. The j-independence number βj(G) is the maximum cardinality of a j-independent set of G. We first establish an inequality between βj(G) and βΔ(G) for 1jδ1. Then we characterize all graphs G with βj(G)=βΔ(G) for j{1,,Δ1}, where the particular cases j=1,2,δ1 and
δ are well distinguished.

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Main Subjects


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