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A decomposition of homomorphic images of nearlattices

Ivan Chajda, Miroslav Kolařík (2006)

Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica

By a nearlattice is meant a join-semilattice where every principal filter is a lattice with respect to the induced order. The aim of our paper is to show for which nearlattice 𝒮 and its element c the mapping ϕ c ( x ) = x c , x p c is a (surjective, injective) homomorphism of 𝒮 into [ c ) × ( c ] .

A note on cylindric lattices

Ivo Düntsch (1993)

Banach Center Publications

0. Introduction. Besides being of intrinsic interest, cylindric (semi-) lattices arise naturally from the study of dependencies in relational databases; the polynomials on a cylindric semilattice are closely related to the queries obtainable from project-join mappings on a relational database (cf. [D] for references). This note is intended to initiate the study of these structures, and only a few, rather basic results will be given. Some problems at the end will hopefully stimulate further research....

A scheme for congruence semidistributivity

Ivan Chajda, Eszter K. Horváth (2003)

Discussiones Mathematicae - General Algebra and Applications

A diagrammatic statement is developed for the generalized semidistributive law in case of single algebras assuming that their congruences are permutable. Without permutable congruences, a diagrammatic statement is developed for the ∧-semidistributive law.


Mahdeieh Abbasloo, Arsham Borumand Saeid (2011)

Discussiones Mathematicae - General Algebra and Applications

In this paper, we introduce the notion of a bi-BL-algebra, bi-filter, bi-deductive system and bi-Boolean elements of a bi-BL-algebra and deal with bi-filters in bi-BL-algebra. We study this structure and construct the quotient of bi-BL-algebra. Also present a classification for examples of proper bi-BL-algebras.

Boolean graphs

Juhani Nieminen (1988)

Commentationes Mathematicae Universitatis Carolinae

Cocycle condition for multi-pullbacks of algebras

Piotr M. Hajac, Bartosz Zieliński (2012)

Banach Center Publications

Take finitely many topological spaces and for each pair of these spaces choose a pair of corresponding closed subspaces that are identified by a homeomorphism. We note that this gluing procedure does not guarantee that the building pieces, or the gluings of some pieces, are embedded in the space obtained by putting together all given ingredients. Dually, we show that a certain sufficient condition, called the cocycle condition, is also necessary to guarantee sheaf-like properties of surjective multi-pullbacks...

Finite closed coverings of compact quantum spaces

Piotr M. Hajac, Atabey Kaygun, Bartosz Zieliński (2012)

Banach Center Publications

We consider the poset of all non-empty finite subsets of the set of natural numbers, use the poset structure to topologise it with the Alexandrov topology, and call the thus obtained topological space the universal partition space. Then we show that it is a classifying space for finite closed coverings of compact quantum spaces in the sense that any such a covering is functorially equivalent to a sheaf over this partition space. In technical terms, we prove that the category of finitely supported...

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