Distinguishing partitions and asymmetric uniform hypergraphs
Abstract
A distinguishing partition for an action of a group Γ on a set X is a partition of X that is preserved by no nontrivial element of Γ. As a special case, a distinguishing partition of a graph is a partition of the vertex set that is preserved by no nontrivial automorphism. In this paper we provide a link between distinguishing partitions of complete equipartite graphs and asymmetric uniform hypergraphs. Suppose that m ≥ 1 and n ≥ 2. We show that an asymmetric n-uniform hypergraph with m edges exists if and only if m ≥ f(n), where f(2) = f(14) = 6, f(6) = 5, and f(n)= ⌊ log2(n + 1) ⌋ + 2 otherwise. It follows that a distinguishing partition of Km(n) = Kn, n, ..., n, or equivalently for the wreath product action Sn Wr Sm, exists if and only if m ≥ f(n).
Keywords
complete equipartite graph, distinguishing number, distinguishing partition, asymmetric uniform hypergraph
DOI: https://doi.org/10.26493/1855-3974.195.d00
ISSN: 1855-3974
Issues from Vol 6, No 1 onward are partially supported by the Slovenian Research Agency from the Call for co-financing of scientific periodical publications