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On Distributive Fixed-Point Expressions

Helmut Seidl, Damian Niwiński (2010)

RAIRO - Theoretical Informatics and Applications

For every fixed-point expression e of alternation-depth r, we construct a new fixed-point expression e' of alternation-depth 2 and size 𝒪 ( r · | e | ) . 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 extended frames

Jorge Picado (1995)

Commentationes Mathematicae Universitatis Carolinae

Some aspects of extended frames are studied, namely, the behaviour of ideals, covers, admissible systems of covers and uniformities.

On free M V -algebras

Ján Jakubík (2003)

Czechoslovak Mathematical Journal

In the present paper we show that free M V -algebras can be constructed by applying free abelian lattice ordered groups.

On fuzzy ideals of pseudo MV-algebras

Grzegorz Dymek (2008)

Discussiones Mathematicae - General Algebra and Applications

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 idempotent modifications of M V -algebras

Ján Jakubík (2007)

Czechoslovak Mathematical Journal

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 M V -algebra 𝒜 we denote by 𝒜 ' , A and ( 𝒜 ) the idempotent modification, the underlying set or the underlying lattice of 𝒜 , respectively. In the present paper we prove that if 𝒜 is semisimple and ( 𝒜 ) is a chain, then 𝒜 ' is subdirectly irreducible. We deal also with a question of Ježek concerning varieties of algebras.

On intervals and isometries of M V -algebras

Ján Jakubík (2002)

Czechoslovak Mathematical Journal

Let Int 𝒜 be the lattice of all intervals of an M V -algebra 𝒜 . In the present paper we investigate the relations between direct product decompositions of 𝒜 and (i) the lattice Int 𝒜 , or (ii) 2-periodic isometries on 𝒜 , respectively.

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