A Cayley graph Cay(G, S) of a group G is called a CI-graph if whenever T is another subset of G for which Cay(G, S) βΌ = Cay(G, T ), there exists an automorphism Ο of G such that S Ο = T . For a positive integer m, the group G is said to have the m-CI property if all Cayley graphs of G of valency m a
On Isomorphisms of Connected Cayley Graphs, II
β Scribed by Cai Heng Li
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 182 KB
- Volume
- 74
- Category
- Article
- ISSN
- 0095-8956
No coin nor oath required. For personal study only.
β¦ Synopsis
A Cayley graph or digraph Cay(G, S) of a finite group G is called a CI-graph of G if, for any T/G, Cay(G, S)$Cay(G, T) if and only if S _ =T for some _ # Aut(G). We study the problem of determining which Cayley graphs and digraphs for a given group are CI-graphs. A finite group G is called a connected m-DCI-group (or connected m-CI-group) if all connected Cayley digraphs (or connected Cayley graphs, respectively) of G of (out)-valency at most m are CI-graphs. For a group G, let p(G) be the smallest prime divisor of |G|. It was previously shown that all finite groups G are connected ( p(G)&1)-DCI-groups and all finite groups G are connected 2( p(G)&1)-CI-groups. In this paper, for every prime p, we construct infinitely many finite groups G such that p(G)= p and G is neither a connected p-DCI-group nor a connected 2 p-CI-group, which provides solutions for several open problems in this area.
π SIMILAR VOLUMES
The issue of when two Cayley digraphs on different abelian groups of prime power order can be isomorphic is examined. This had previously been determined by Anne Joseph for squares of primes; her results are extended.
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For a subset S of a group G such that 1 / β S and S = S -1 , the associated Cayley graph Cay(G, S) is the graph with vertex set G such that {x, y} is an edge if and only if yx -1 β S. Each Ο β Aut(G) induces an isomorphism from Cay(G, S) to the Cayley graph Cay(G, S Ο ). For a positive integer m, th
## Abstract Let __Z__~__p__~ denote the cyclic group of order __p__ where __p__ is a prime number. Let __X__ = __X__(__Z__~__p__~, __H__) denote the Cayley digraph of __Z__~__p__~ with respect to the symbol __H__. We obtain a necessary and sufficient condition on __H__ so that the complete graph on