On a hierarchy of groups of computable automorphisms.
On a sufficient condition for strong constructivizability of atomic Boolean algebras.
On constructive nilpotent groups.
On constructivizability of the tensor product of modules.
On effective presentations of formal concept lattices.
On elementary cuts in recursively saturated models of Peano Arithmetic
On extending automorphisms of models of Peano Arithmetic
Continuing the earlier research in [10] we give some information on extending automorphisms of models of PA to end extensions and cofinal extensions.
On problems of databases over a fixed infinite universe
In the relational model of databases a database state is thought of as a finite collection of relations between elements. For many applications it is convenient to pre-fix an infinite domain where the finite relations are going to be defined. Often, we also fix a set of domain functions and/or relations. These functions/relations are infinite by their nature. Some special problems arise if we use such an approach. In the paper we discuss some of the problems. We show that there exists a recursive...
On quasiresolvent periodic Abelian groups.
On the Ershov upper semilattice .
On the existence of super-decomposable pure-injective modules over strongly simply connected algebras of non-polynomial growth
Assume that k is a field of characteristic different from 2. We show that if Γ is a strongly simply connected k-algebra of non-polynomial growth, then there exists a special family of pointed Γ-modules, called an independent pair of dense chains of pointed modules. Then it follows by a result of Ziegler that Γ admits a super-decomposable pure-injective module if k is a countable field.
On the index sets of -subsets of the real numbers.
On the problem of finite signature.
On the relation of -reducibility between admissible sets.