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Equimorphy in varieties of distributive double p -algebras

Václav Koubek, Jiří Sichler (1998)

Czechoslovak Mathematical Journal

Any finitely generated regular variety 𝕍 of distributive double p -algebras is finitely determined, meaning that for some finite cardinal n ( 𝕍 ) , any subclass S ⊆ 𝕍 of algebras with isomorphic endomorphism monoids has fewer than n ( 𝕍 ) pairwise non-isomorphic members. This result follows from our structural characterization of those finitely generated almost regular varieties which are finitely determined. We conjecture that any finitely generated, finitely determined variety of distributive double p -algebras...

Equimorphy in varieties of double Heyting algebras

V. Koubek, J. Sichler (1998)

Colloquium Mathematicae

We show that any finitely generated variety V of double Heyting algebras is finitely determined, meaning that for some finite cardinal n(V), any class 𝒮 ⊆ V consisting of algebras with pairwise isomorphic endomorphism monoids has fewer than n(V) pairwise non-isomorphic members. This result complements the earlier established fact of categorical universality of the variety of all double Heyting algebras, and contrasts with categorical results concerning finitely generated varieties of distributive...

Finitely generated almost universal varieties of 0 -lattices

Václav Koubek, Jiří Sichler (2005)

Commentationes Mathematicae Universitatis Carolinae

A concrete category 𝕂 is (algebraically) universal if any category of algebras has a full embedding into 𝕂 , and 𝕂 is almost universal if there is a class 𝒞 of 𝕂 -objects such that all non-constant homomorphisms between them form a universal category. The main result of this paper fully characterizes the finitely generated varieties of 0 -lattices which are almost universal.

Lattices and semilattices having an antitone involution in every upper interval

Ivan Chajda (2003)

Commentationes Mathematicae Universitatis Carolinae

We study ∨ -semilattices and lattices with the greatest element 1 where every interval [p,1] is a lattice with an antitone involution. We characterize these semilattices by means of an induced binary operation, the so called sectionally antitone involution. This characterization is done by means of identities, thus the classes of these semilattices or lattices form varieties. The congruence properties of these varieties are investigated.

Natural extension of a congruence of a lattice to its lattice of convex sublattices

S. Parameshwara Bhatta, H. S. Ramananda (2011)

Archivum Mathematicum

Let L be a lattice. In this paper, corresponding to a given congruence relation Θ of L , a congruence relation Ψ Θ on C S ( L ) is defined and it is proved that 1. C S ( L / Θ ) is isomorphic to C S ( L ) / Ψ Θ ; 2. L / Θ and C S ( L ) / Ψ Θ are in the same equational class; 3. if Θ is representable in L , then so is Ψ Θ in C S ( L ) .

Note on "construction of uninorms on bounded lattices"

Xiu-Juan Hua, Hua-Peng Zhang, Yao Ouyang (2021)

Kybernetika

In this note, we point out that Theorem 3.1 as well as Theorem 3.5 in G. D. Çaylı and F. Karaçal (Kybernetika 53 (2017), 394-417) contains a superfluous condition. We have also generalized them by using closure (interior, resp.) operators.

Notes on locally internal uninorm on bounded lattices

Gül Deniz Çaylı, Ümit Ertuğrul, Tuncay Köroğlu, Funda Karaçal (2017)

Kybernetika

In the study, we introduce the definition of a locally internal uninorm on an arbitrary bounded lattice L . We examine some properties of an idempotent and locally internal uninorm on an arbitrary bounded latice L , and investigate relationship between these operators. Moreover, some illustrative examples are added to show the connection between idempotent and locally internal uninorm.

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