3 citations · 5 across the 9 of their papers we have counts for
11 papers
Consequence Relations An Introduction to the Tarski-Lindenbaum Method
Alex Citkin, Alexei Muravitsky
The book is devoted to the study of the field of application of the method, which arose from the concept of the Lindenbaum matrix by A. Lindenbaum and the Lindenbaum theorem, withi…
Lindenbaum Method
Alex Citkin, Alexei Muravitsky
During his brief life, the Polish mathematician and logician Adolf Lindenbaum (1904--1941) contributed to mathematical logic, among other things, by several significant achievement…
Projective Algebras and Primitive Subquasivarieties in Varieties with Factor Congruences
Alex Citkin
We prove that in the varieties where every compact congruence is a factor congruence and every nontrivial algebra contains a minimal subalgebra, a finitely presented algebra is pro…
Hereditarily Structurally Complete Superintuitionistic Deductive Systems
Alex Citkin
The paper studies hereditarily complete superintuitionistic deductive systems, that is, the deductive system which logic is an extension of the intuitionistic propositional logic.…
Admissibility in Positive Logics
Alex Citkin
The paper studies admissibility of multiple-conclusion rules in the positive logics. Using modification of a method used by M.~Wajsberg in the proof of the separation theorem, it i…
Lindenbaum method (propositional language)
Alex Citkin, Alexei Muravitsky
Lindenbaum method is named after the Polish logician Adolf Lindenbaum who prematurely and without a clear trace disappeared in the turmoil of the Second World War at the age of abo…
Multiple Conclusion Rules in Logics with the Disjunction Property
Alex Citkin
We prove that for the intermediate logics with the disjunction property any basis of admissible rules can be reduced to a basis of admissible m-rules (multiple-conclusion rules), a…
A Meta-Logic of Inference Rules: Syntax
Alex Citkin
This work was intended to be an attempt to introduce the meta-language for working with multiple-conclusion inference rules that admit asserted propositions along with the rejected…
Characteristic Formulas 50 Years Later (An Algebraic Account)
Alex Citkin
The Jankov (characteristic) formulas were introduced by V.Jankov fifty tears ago in 1963. Nowadays the Jankov (or frame) formulas are used in virtually every branch of propositiona…
Ł-Axiomatizability in intermediate and normal modal logics
Alex Citkin
A set of formulas is complete relative to a given class of logics, if every logic from this class can be axiomatized by formulas from . A set of formulas is Ł-complete r…
Characteristic formulas over intermediate logics
Alex Citkin
We expand the notion of characteristic formula to infinite finitely presentable subdirectly irreducible algebras. We prove that there is a continuum of varieties of Heyting algebra…