Vertex‐transitive graphs that remain connected after failure of a vertex and its neighbors
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2011Suggested citation
Hamidoune, Yahya Ould;
Lladó, Anna;
López Masip, SusanaClara;
.
(2011)
.
Vertex‐transitive graphs that remain connected after failure of a vertex and its neighbors.
Journal of Graph Theory, 2011, vol. 67, num. 2, p. 124138.
https://doi.org/10.1002/jgt.20521.
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A dregular graph is said to be superconnected if any disconnecting subset with cardinality at most d is formed by the neighbors of some vertex. A superconnected graph that remains connected after the failure of a vertex and its neighbors will be called vosperian. Let Γ be a vertextransitive graph of degree d with order at least d+4. We give necessary and sufficient conditions for the vosperianity of Γ. Moreover, assuming that distinct vertices have distinct neighbors, we show that Γ is vosperian if and only if it is superconnected. Let G be a group and let S ⊂ G \ {1} with S = S −1 . We show that the Cayley graph, Cay(G, S), defined on G by S is vosperian if and only if G \ (S ∪ {1}) is not a progression and for every non trivial subgroup H and every a ∈ G, (H ∪ Ha)(S ∪ {1}) ≥ min(G − 1, H ∪ Ha + S + 1). If moreover S is aperiodic, then Cay(G, S) is vosperian if and only if it is superconnected.
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Journal of Graph Theory, 2011, vol. 67, num. 2, p. 124138European research projects
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