Results 71 to 80 of about 167 (147)
On Closedness of Some Homotypical Varieties of Semigroups
Journal of Mathematics, Volume 2024, Issue 1, 2024.It is well known that every subvariety of the variety of semigroups need not be absolutely closed. Thus, identifying those subvarieties that are closed in themselves or in larger varieties is an interesting open problem in the theory of semigroup dominions.
Noor Alam +6 more
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Identities in implicative semilattices [PDF]
Proceedings of the American Mathematical Society, 1973 An effective procedure is given for deciding whether or not an equation in the theory of implicative semilattices is an identity.
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Choice principles and lift lemmas [PDF]
Categories and General Algebraic Structures with Applications, 2017 We show that in {bf ZF} set theory without choice, the Ultrafilter mbox{Principle} ({bf UP}) is equivalent to several compactness theorems for Alexandroff discrete spaces and to Rudin's Lemma, a basic tool in topology and the theory of quasi-continuous ...
Marcel Ern'e
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Fuzzy Ideals and Fuzzy Filters of Pseudocomplemented Semilattices
Advances in Fuzzy Systems, 2019 In this paper, we introduce the concept of kernel fuzzy ideals and ⁎-fuzzy filters of a pseudocomplemented semilattice and investigate some of their properties.
Berhanu Assaye Alaba +1 more
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c-ideals in complemented posets [PDF]
Mathematica BohemicaIn their recent paper on posets with a pseudocomplementation denoted by $*$ the first and the third author introduced the concept of a $*$-ideal. This concept is in fact an extension of a similar concept introduced in distributive pseudocomplemented ...
Ivan Chajda +2 more
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Theoretical Computer Science, 1986 A subset system \({\mathcal Z}\) is an operator assigning to each poset P a collection \({\mathcal Z}(P)\) of subsets of P such that for each \(X\in {\mathcal Z}(P)\) and each order-preserving \(f: P\to Q\) we have f(X)\(\in {\mathcal Z}(Q)\). A poset P is \({\mathcal Z}\)-complete iff each \(X\in {\mathcal Z}(P)\) has a join in P.
Adámek, J., Reiterman, J., Nelson, E.
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Subject-matter and intensional operators I: conditional-agnostic analytic implication. [PDF]
Philos Stud, 2023 Ferguson TM.
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Compactable semilattices [PDF]
Semigroup Forum, 2010 We characterize those semilattices that give rise to Boolean spaces on their associated spaces of ultrafilters. The class of 0-disjunctive semilattices, important in the theory of congruence-free inverse semigroups, plays a distinguished role in this theory.
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Topological and ditopological unosemigroups [PDF]
Математичні Студії, 2013 In this paper we introduce and study a new topologo-algebraic structure called a (di)topological unosemigroup. This is a topological semigroup endowed with continuous unary operations of left and right units (which have certain continuous division ...
T. Banakh, I. Pastukhova
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