Results 21 to 30 of about 309 (55)

Closures of regular languages for profinite topologies [PDF]

, 2014
The Pin-Reutenauer algorithm gives a method, that can be viewed as a descriptive procedure, to compute the closure in the free group of a regular language with respect to the Hall topology.
A Moura, AW Anissimow, B Herwig, B Steinberg, B Steinberg, CJ Ash, J Almeida, J Almeida, J Almeida, J Almeida, J Almeida, J Almeida, J Almeida, J Almeida, J Almeida, J Almeida, J Almeida, J-É Pin, J. Almeida, J. C. Costa, JC Costa, JP McCammond, K Auinger, K Auinger, K Henckell, K Henckell, K Henckell, K Numakura, L Ribes, M. Zeitoun   +29 more
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Tameness of pseudovariety joins involving R [PDF]

, 2004
2000 Mathematics Subject Classification: 20M07 (primary); 20M05, 20M35, 68Q70 (secondary).In this paper, we establish several decidability results for pseudovariety joins of the form VvW, where V is a subpseudovariety of J or the pseudovariety R.
B Herwig, B Steinberg, CJ Ash, D Albert, J Almeida, J Almeida, J Almeida, J Almeida, J Almeida, J Almeida, J Almeida, J Almeida, J Almeida, J Almeida, J Almeida, J Almeida, J Almeida, J Rhodes, J-E Pin, JC Costa, JC Costa, Jorge Almeida, José Carlos Costa, K Auinger, M Zeitoun, Marc Zeitoun, Th Coulbois   +26 more
core   +4 more sources

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
core   +1 more source

Semidirect product with an order-computable pseudovariety and tameness [PDF]

, 2010
Dedicated to the memory of Walter Douglas Munn.The semidirect product of pseudovarieties of semigroups with an ordercomputable pseudovariety is investigated.
Almeida, Jorge, Costa, José Carlos, Teixeira, M. Lurdes   +2 more
core   +3 more sources

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, Costa, José Carlos, Zeitoun, Marc   +2 more
core   +2 more sources

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  

The lattice of varieties of implication semigroups [PDF]

, 2019
In 2012, the second author introduced and examined a new type of algebras as a generalization of De Morgan algebras. These algebras are of type (2,0) with one binary and one nullary operation satisfying two certain specific identities.
Gusev, S. V., Sankappanavar, H. P., Vernikov, B. M.   +2 more
core   +1 more source

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  

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, Pin, Jean-Éric, Ésik, Zoltán   +2 more
core   +1 more source

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, Costa, José Carlos, Zeitoun, Marc   +2 more
core   +2 more sources