Regular subgroups with large intersection

Semi-regular relative difference sets with large forbidden subgroups

Article history: Received 19 October 2007 Available online 16 April 2008 Communicated by Charles J. Colbourn

Normal Circulant Graphs with Noncyclic Regular Subgroups

Intersection subgroups of complex hyperplane arrangements

A X g. We exhibit natural embeddings of M(A X) in M(A) that give rise to monomorphisms from 1 (M(A X)) to 1 (M(A)). We call the images of these monomorphisms intersection subgroups of type X and prove that they form a conjugacy class of subgroups of 1 (M(A)). Recall that X in L(A) is modular if X+Y is an element of L(A) for all Y in L(A). We call X in L(A) supersolvable if there exists a chain ...

Regular Subgroups of a Transitive Substitution Group.

On the intersection of regex languages with regular languages

In this paper we revisit the semantics of extended regular expressions (regex), defined succinctly in the 90s [A.V. Aho, Algorithms for finding patterns in strings, in: Jan van Leeuwen (Ed.), Handbook of Theoretical Computer Science, in: Algorithms and Complexity, vol. A, Elsevier and MIT Press, 1990, pp. 255–300] and rigorously in 2003 by Câmpeanu, Salomaa and Yu [C. Câmpeanu, K. Salomaa, S. Y...