Power monoids and finite J-trivial monoids.
Power pseudovarieties of semigroups I.
Power pseudovarieties of semigroups II.
Pre-solid varieties of semigroups
Pre-hyperidentities generalize the concept of a hyperidentity. A variety is said to be pre-solid if every identity in is a pre-hyperidentity. Every solid variety is pre-solid. We consider pre-solid varieties of semigroups which are not solid, determine the smallest and the largest of them, and some elements in this interval.
Pre-strongly solid varieties of commutative semigroups
Generalized hypersubstitutions are mappings from the set of all fundamental operations into the set of all terms of the same language do not necessarily preserve the arities. Strong hyperidentities are identities which are closed under the generalized hypersubstitutions and a strongly solid variety is a variety which every its identity is a strong hyperidentity. In this paper we give an example of pre-strongly solid varieties of commutative semigroups and determine the least and the greatest pre-strongly...
Pseudovarieties of completely regular semigroups.