unipotent elements
1.In chapter 2, we prove that an abundant semigroup satisfying the regularity is a locally E-solid [resp. quasi-adequate; R*- unipotent] semigroup if and only if it is an E-local isomorphic image of some abundant Rees matrix semigroup AM(T; I, A; P) over an E-solid abundant [resp. quasi-adequate; R*- unipotent] semigroup with entries of the sandwich matrix P being regular elements of T.
