RECOGNIZABLE LANGUAGES AND FINITE SEMILATTICES OF GROUPS.
Relative commutator associated with varieties of -nilpotent and of -solvable groups
In this note we determine explicit formulas for the relative commutator of groups with respect to the subvarieties of -nilpotent groups and of -solvable groups. In particular these formulas give a characterization of the extensions of groups that are central relatively to these subvarieties.
Remarks on Varieties of Topological Groups
Representations of Certain Verbal Wreath Products by Matrices.
Residual ...-Centrality in Groups.