Polovitskii Ya. D.
Ukr. Mat. Zh. - 1997. - 49, № 4. - pp. 566–572
We introduce a new type of conditions, S-obligatory conditions. We describe broad classes of groups with the Chernikov obligatory condition and some other conditions similar to the known Fedorov condition.
Ukr. Mat. Zh. - 1996. - 48, № 4. - pp. 533-539
We give a description of groups with incidence condition for noncyclic subgroups to within minimal noncyclic subgroups. We present a complete constructive description of locally graded groups (in particular, arbitrary locally finite groups) satisfying this condition.
Ukr. Mat. Zh. - 1992. - 44, № 6. - pp. 847–851