Minimal Presentations and Embedding into Inefficient Semigroups
Hayrullah Ayık, Melis Minisker, Bilal Vatansever · Algebra Colloquium · 2005
In this paper, we show that CLn, the chain with n elements, is efficient and that the direct product CLm× CLnis inefficient. Moreover, we embed any finitely presented semigroup S into an inefficient semigroup, namely, the semigroup S ⋃ SLn, where SLnis the free semilattice of rank n.