A modal logic is called invariant if for all automorphisms of NExt K, () = . An invariant logic is therefore uniquely determined by its surrounding in the lattice. It will be est...
Let K x, y be the free associative algebra of rank 2 over an algebraically closed constructive field of any characteristic. We present an algorithm which decides whether or not tw...
A transitive decomposition of a graph is a partition of the edge set together with a group of automorphisms which transitively permutes the parts. In this paper we determine all t...
Alice Devillers, Michael Giudici, Cai Heng Li, Che...
Automorphisms of Steiner 2-designs S(2, 4, 37) are studied and used to find many new examples. Some of the constructed designs have S(2, 3, 9) subdesigns, closing the last gap in t...