Densely embedded ideals of semigroups

The main result of this paper is the following theorem: A semigroup with equi-operative elements cannot be a densely embedded ideal of a semigroup. This theorem, by generalizing an earlier result by the author, solves a problem that has remained open for a number of years. In conjunction with some results by L. M. Gluskin, this yields several corollaries containing conclusive results with regard to densely embedded ideals.
Bibliography: 14 titles.