An Equal Complement About Periodic Rectangular Groups
TV Untversity · 1994
The article has proved the conclusion as follows:Let sernigroup S =R×L is direct product of semigroup R and L. then for all subsemigroup T of S, there exists subsemigroup Rf and L' of R and L, such that T=R'× L',if and only if S is the direct product of a rectangular band and a periodic group.