A groupoid characterization of Boolean algebras
We present a groupoid which can be converted into a Boolean algebra with respect to term operations. Also conversely, every Boolean algebra can be reached in this way.
A property of stable theories
A sufficient condition for a variety to have the amalgamation property
Applications logiques en théorie des anneaux et des modules
Completely dissociative groupoids
In a groupoid, consider arbitrarily parenthesized expressions on the variables where each appears once and all variables appear in order of their indices. We call these expressions -ary formal products, and denote the set containing all of them by . If are distinct, the statement that and are equal for all values of is a generalized associative law. Among other results, we show that many small groupoids are completely dissociative, meaning that no generalized associative law holds...
Congruence relations on finitary models
Equationally compact algebras (I)
Equationally compact algebras II
Equationally compact algebras (III)
Errata for the paper "Equationally compact algebras II" (Fundamenta Mathematica 61 (1968), pp. 271-281)
Factorable congruences and strict refinement.
Free Suslin algebras
Hyperidentities in associative graph algebras
Graph algebras establish a connection between directed graphs without multiple edges and special universal algebras of type (2,0). We say that a graph G satisfies an identity s ≈ t if the correspondinggraph algebra A(G) satisfies s ≈ t. A graph G is called associative if the corresponding graph algebra A(G) satisfies the equation (xy)z ≈ x(yz). An identity s ≈ t of terms s and t of any type τ is called a hyperidentity of an algebra A̲ if whenever the operation symbols occurring in s and t are replaced...
Induced algebras
Linear identities in graph algebras
We find the basis of all linear identities which are true in the variety of entropic graph algebras. We apply it to describe the lattice of all subvarieties of power entropic graph algebras.
On a question of Pultr regarding categories of structures
On compact classes of models
On countably compact reduced products, III
On generalized products preserving compactness.
On relational selections for complete theories.