On a property of groups with coverings.
On a pull-back diagram for orthodox semigroups.
On a question of Chambers and Makan.
On a question of Deaconescu about automorphisms
On a question of Deaconescu about automorphisms. - II
On a question of Deaconescu about automorphisms. - III
On a question of M. Conder
We show that the special linear group , over the integers, is not -generated. This gives a negative answer to a question of M. Conder.
On a relationship between monoids and monounary algebras
On a representation of groupoids as sums of directed systems
On a representation of semigroups by products of algebras and relations
On a result of G. Baumslag
On a result of Williamson.
On a semigroup theoretic generalization of the Kaluznin Krasner Theorem and normal extensions of inverse semigroups.
On a sequence of K. A. Hardie
On a simple one-element extension of left zero semigroups
On a subclass of context-free groups
On a subgroup of the affine Weyl group .
On a sublattice- of the lattice of congruences on a 0-regular semigroup.
On a technique for representing semigroups as endomorphism semigroups of graphs with given property.
On a theorem of Baumslag, Dyer and Heller linking group theory and topology