On saturating ultrafilters on N
On Scheepers' conjecture
On Semantics of a Term Calculus for Classical Logic
On semialgebraic points of definable sets
We prove that the semialgebraic, algebraic, and algebraic nonsingular points of a definable set in o-minimal structure with analytic cell decomposition are definable. Moreover, the operation of taking semialgebraic points is idempotent and the degree of complexity of semialgebraic points is bounded.
On Semi-Boolean-Like Algebras
In a previous paper, we introduced the notion of Boolean-like algebra as a generalisation of Boolean algebras to an arbitrary similarity type. In a nutshell, a double-pointed algebra with constants is Boolean-like in case for all the congruences and are complementary factor congruences of . We also introduced the weaker notion of semi-Boolean-like algebra, showing that it retained some of the strong algebraic properties characterising Boolean algebras. In this paper, we continue the investigation...
On semisimple bands.
On sensible fuzzy ideals of BCK-algebras with respect to a t-conorm.
On sentences provable in impredicative extensions of theories [Book]
On separation axioms in intuitionistic topological spaces.
On separation properties for families of probability measures.
On sequent calculi for intuitionistic propositional logic
The well-known Dyckoff's 1992 calculus/procedure for intuitionistic propositional logic is considered and analyzed. It is shown that the calculus is Kripke complete and the procedure in fact works in polynomial space. Then a multi-conclusion intuitionistic calculus is introduced, obtained by adding one new rule to known calculi. A simple proof of Kripke completeness and polynomial-space decidability of this calculus is given. An upper bound on the depth of a Kripke counter-model is obtained.
On sequentially Ramsey sets
On sets with rank one in simple homogeneous structures
We study definable sets D of SU-rank 1 in , where ℳ is a countable homogeneous and simple structure in a language with finite relational vocabulary. Each such D can be seen as a ’canonically embedded structure’, which inherits all relations on D which are definable in , and has no other definable relations. Our results imply that if no relation symbol of the language of ℳ has arity higher than 2, then there is a close relationship between triviality of dependence and being a reduct of a binary...
On Sigma10-extensions of Omega
On Some Classes Of Unrecognizable Properties Of Groups
On some classes of unrecognizable properties of groups.
On some combinatorial problems involving large cardinals
On some conjectures connected with complete sentences
On some connections between Boolean algebras and Heyting algebras
On some constructions of algebraic objects
Mono-unary algebras may be used to construct homomorphisms, subalgebras, and direct products of algebras of an arbitrary type.