562 research outputs found
Some identities for enumerators of circulant graphs
We establish analytically several new identities connecting enumerators of
different types of circulant graphs of prime, twice prime and prime-squared
orders. In particular, it is shown that the semi-sum of the number of
undirected circulants and the number of undirected self-complementary
circulants of prime order is equal to the number of directed self-complementary
circulants of the same order.
Keywords: circulant graph; cycle index; cyclic group; nearly doubled primes;
Cunningham chain; self-complementary graph; tournament; mixed graphComment: 17 pages, 3 tables Categories: CO Combinatorics (NT Number Theory)
Math Subject Class: 05C30; 05A19; 11A4
Zero Forcing Sets and Bipartite Circulants
In this paper we introduce a class of regular bipartite graphs whose
biadjacency matrices are circulant matrices and we describe some of their
properties. Notably, we compute upper and lower bounds for the zero forcing
number for such a graph based only on the parameters that describe its
biadjacency matrix. The main results of the paper characterize the bipartite
circulant graphs that achieve equality in the lower bound.Comment: 22 pages, 13 figure
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