-compatible identities and their applications to classical algebras
Permutability, Distributivity of Equivalence Relations and Direct Products
Permutability of congruences in varieties with idempotent operations
Permutability of distributive congruence relations in a joint semilattice directed below
Permutability of tolerances with factor and decomposing congruences.
Polynome und algebraische Gleichungen über universalen Algebren.
Polynomial Interpolation and the Chinese Remainder Theorem for Algebraic Systems.
Polynomial Interpolation for Locally Equational Classes.
Polynomials in idempotent commutative groupoids [Book]
Poproduct of Lattices and Sorkin's Theorem
Positively conditional pseudovarieties and implicit operations on them.
Präprimale Algebren, die arithmetische Varietäten erzeugen
Precomplete varieties of semigroups.
Preservation Theorems for Limits of Structures and Global Sections of Sheaves of Structures.
Presolid varieties of n-semigroups
he class of all M-solid varieties of a given type t forms a complete sublattice of the lattice ℒ(τ) of all varieties of algebrasof type t. This gives a tool for a better description of the lattice ℒ(τ) by characterization of complete sublattices. In particular, this was done for varieties of semigroups by L. Polák ([10]) as well as by Denecke and Koppitz ([4], [5]). Denecke and Hounnon characterized M-solid varieties of semirings ([3]) and M-solid varieties of groups were characterized by Koppitz...
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...
Prime ideals in universal algebras
Primitive classes of algebras with two unary idempotent operations, containing all algebraic categories as full subcategories
Principal tolerances on lattices