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Unretractive and S-unretractive joins and lexicographic products of graphs

✍ Scribed by Ulrich Knauer

Publisher
John Wiley and Sons
Year
1987
Tongue
English
Weight
515 KB
Volume
11
Category
Article
ISSN
0364-9024

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✦ Synopsis

Graphs without proper endomorphisms are the subject of this article. It is shown that the join of two graphs has this property if and only if both summands have it, and that the lexicographic product of a complete graph or an odd circuit as first factors has this property if and only if the second factor has it. A somewhat stronger theorem is proved if the lexicographic product has no proper strong endomorphism. The corresponding result for the join is the same as for usual endomorphisms.

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