On completely meet-irreducible elements in compactly generated lattices
On congruences of ...x-normal semigroups.
On connections between information systems, rough sets and algebraic logic
In this note we remark upon some relationships between the ideas of an approximation space and rough sets due to Pawlak ([9] and [10]) and algebras related to the study of algebraic logic - namely, cylindric algebras, relation algebras, and Stone algebras. The paper consists of three separate observations. The first deals with the family of approximation spaces induced by the indiscernability relation for different sets of attributes of an information system. In [3] the family of closure operators...
On constructing a distributive lattice from a partially ordered set with DCC
On convex constructions in lattices
On cyclic symmetric Heyting algebras.
On distributive fixed-point expressions
On Distributive Fixed-Point Expressions
For every fixed-point expression e of alternation-depth r, we construct a new fixed-point expression e' of alternation-depth 2 and size . Expression e' is equivalent to e whenever operators are distributive and the underlying complete lattice has a co-continuous least upper bound. We alternation-depth but also w.r.t. the increase in size of the resulting expression.
On equalizers in the category of frames with weakly open homomorphisms
On existence conditions for compatible tolerances
On extended frames
Some aspects of extended frames are studied, namely, the behaviour of ideals, covers, admissible systems of covers and uniformities.
On forbidden configuration of -distributive lattices
In this paper we obtain the forbidden configuration for 0-distributive lattices.
On frame congruences generated by frame tolerances
Nuclei of frame congruences generated by frame tolerances and by lattice congruences are constructed.
On free -algebras
In the present paper we show that free -algebras can be constructed by applying free abelian lattice ordered groups.
On fuzzy ideals of pseudo MV-algebras
Fuzzy ideals of pseudo MV-algebras are investigated. The homomorphic properties of fuzzy prime ideals are given. A one-to-one correspondence between the set of maximal ideals and the set of fuzzy maximal ideals μ satisfying μ(0) = 1 and μ(1) = 0 is obtained.
On generalized MS-Algebras
On H. Priestley's dual of the category of bounded distributive lattices
On idempotent modifications of -algebras
The notion of idempotent modification of an algebra was introduced by Ježek. He proved that the idempotent modification of a group is subdirectly irreducible. For an -algebra we denote by and the idempotent modification, the underlying set or the underlying lattice of , respectively. In the present paper we prove that if is semisimple and is a chain, then is subdirectly irreducible. We deal also with a question of Ježek concerning varieties of algebras.
On imaginable -fuzzy subalgebras and imaginable -fuzzy closed ideals in BCH-algebras.
On interval subalgebras of generalized MV-algebras