Almost Cross Varieties of Aperiodic Monoids with Central Idempotents
Beiträge zur Algebra und Geometrie
Monoid, Aperiodic monoid, Central idempotent, Cross varieties, Variety
It is known that the class A of aperiodic monoids with central idempotents contains precisely two finitely generated, almost Cross subvarieties. The present article exhibits the first example of a non-finitely generated, almost Cross subvariety of A and verifies that it is in fact unique. Consequently, the class A contains precisely three almost Cross subvarieties.
Lee, Edmond W. H., "Almost Cross Varieties of Aperiodic Monoids with Central Idempotents" (2013). Mathematics Faculty Articles. 9.