A semigroup embedding problem and an arithmetical function
John M Howie, John L. Selfridge · Mathematical Proceedings of the Cambridge Philosophical Society · 1991
For unexplained terms in semigroup theory see [1] or [4]. Let C, D be classes of semigroups such that every finite semigroup in the class C is embeddable in a finite semigroup in the class D. If n ≥ 2 then k is said to be a C – Dcover of n if every semigroup of order n in the class C is embeddable in a semigroup in the class D of order not greater than k. Let be the least C – D cover of n.