Results 21 to 30 of about 302 (48)
Varieties of Restriction Semigroups and Varieties of Categories [PDF]
, 2017 The variety of restriction semigroups may be most simply described as that generated from inverse semigroups (S, ·, −1) by forgetting the inverse operation and retaining the two operations x+ = xx−1 and x* = x−1x.
Jones, Peter
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Factoriality and the pin-reutenauer procedure [PDF]
, 2016 We consider implicit signatures over finite semigroups determined by sets of pseudonatural numbers. We prove that, under relatively simple hypotheses on a pseudovariety V of semigroups, the finitely generated free algebra for the largest such signature ...
Almeida, Jorge +2 more
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Some pseudovariety joins involving locally trivial semigroups [PDF]
, 2002 This paper is concerned with the computation of pseudovariety joins involving the pseudovariety LI of locally trivial semigroups. We compute, in particular, the join of LI with any subpseudovariety of CRmN, the Mal'cev product of the pseudovariety of ...
Costa, José Carlos
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The FO^2 alternation hierarchy is decidable [PDF]
, 2012 We consider the two-variable fragment FO^2[
Kufleitner, Manfred, Weil, Pascal
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Varieties of Languages in a Category
, 2015 Eilenberg's variety theorem, a centerpiece of algebraic automata theory, establishes a bijective correspondence between varieties of languages and pseudovarieties of monoids.
Adamek, Jiri +3 more
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Commutative positive varieties of languages
, 2017 We study the commutative positive varieties of languages closed under various operations: shuffle, renaming and product over one-letter ...
Almeida, Jorge +2 more
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The rank of variants of nilpotent pseudovarieties
, 2020 We investigate the rank of pseudovarieties defined by several of the variants of nilpotency conditions for semigroups in the sense of Mal'cev. For several of them, we provide finite bases of pseudoidentities.
Almeida, J., Shahzamanian, M. H.
core
Implicit operations on DS [PDF]
, 1991 In this work we illustrate how the study of the topological semigroups of implicit operations of a pseudovariety V can be useful to the knowledge of V.
Azevedo, Assis
core
ω-terms over finite aperiodic semigroups [PDF]
, 2008 This paper provides a characterization of pseudowords over the pseudovariety of all finite aperiodic semigroups that are given by w-terms, that is that can be obtained from the free generators using only multiplication and the w-power.
Almeida, Jorge +2 more
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On the lattice of overcommutative varieties of monoids
, 2017 It is unknown so far, whether the lattice of all varieties of monoids satisfies some non-trivial identity. The objective of this note is to give the negative answer to this question. Namely, we prove that any finite lattice is a homomorphic image of some
Gusev, S. V.
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