On Normal Cayley Graphs and Hom-idempotent Graphs
نویسندگان
چکیده
A graph G is said to be hom-idempotent if there is a homomorphism from G2 to G, and weakly hom-idempotent if for some n ≥ 1 there is a homomorphism from Gn+1 to Gn . We characterize both classes of graphs in terms of a special class of Cayley graphs called normal Cayley graphs. This allows us to construct, for any integer n, a Cayley graph G such that Gn+1 → Gn 6→ Gn−1, answering a question of Hahn, Hell and Poljak [8]. Also, we show that the Kneser graphs are not weakly hom-idempotent, generalizing a result of Albertson and Collins [1] for the Petersen graph.
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ورودعنوان ژورنال:
- Eur. J. Comb.
دوره 19 شماره
صفحات -
تاریخ انتشار 1998