Varieties of aperiodic monoids with central idempotents whose subvariety lattice is distributive (Q2699868)

Here is considered the class \({A_{cen}}\) of aperiodic monoids with central idempotents. The author presents identities for three monoid varieties (parametrizised by a natural number) and claims that a subvariety of \({A_{cen}}\) is distributive (lattice of subvarieties is distributive) if and only if it is contained in one of the three varieties (or its dual) for some value of the parameter. Several references are available only in Russian.