Positive eigenvalues and two-letter generalized words.
Positively conditional pseudovarieties and implicit operations on them.
Positively prime models over a normal basic set.
Power pseudovarieties of semigroups I.
Power pseudovarieties of semigroups II.
Präprimale Algebren, die arithmetische Varietäten erzeugen
Precomplete varieties of semigroups.
Preorders and equivalences generated by commuting relations.
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 Ideal Theorems and systems of finite character
We study several choice principles for systems of finite character and prove their equivalence to the Prime Ideal Theorem in ZF set theory without Axiom of Choice, among them the Intersection Lemma (stating that if is a system of finite character then so is the system of all collections of finite subsets of meeting a common member of ), the Finite Cutset Lemma (a finitary version of the Teichm“uller-Tukey Lemma), and various compactness theorems. Several implications between these statements...
Prime ideals in universal algebras
Primitive classes of algebras with two unary idempotent operations, containing all algebraic categories as full subcategories
Principal dual ideals in lattices of primitive classes
Principal tolerances on lattices
Principal tolerances on lattices
Products of mode varieties and algebras of subalgebras
Products of multialgebras and their fundamental algebras.