306 citations
Counting papers with at most 25 authors, so collaboration author lists do not stand in for the people here.
- Universidade do PortoPT174 papers
- University of CoimbraPT98 papers
- University of MinhoPT81 papers
- University of LisbonPT24 papers
- Centre National de la Recherche ScientifiqueFR22 papers
- Instituto Superior TécnicoPT22 papers
- UCLouvainBE13 papers
- Universidade Federal da BahiaBR13 papers
- Centro de Análise Matemática Geometria e Sistemas DinâmicosPT10 papers
- Pontifícia Universidade Católica do Rio de JaneiroBR10 papers
- Universidad de La LagunaES9 papers
- Universidade Federal do Rio de JaneiroBR9 papers
11 papers · 2 filters
Complete kappa-reducibility of pseudovarieties of the form DRH
Jorge Almeida, Célia Borlido
We denote by kappa the implicit signature that contains the multiplication and the (omega-1)-power. It is proved that for any completely kappa-reducible pseudovariety of groups H,…
Some reducibility properties for pseudovarieties of the form DRH
Célia Borlido
Let H be a pseudovariety of groups and DRH be the pseudovariety containing all finite semigroups whose regular R-classes belong to H. We study the relationship between reducibility…
The rank of variants of nilpotent pseudovarieties
J. Almeida, M. H. Shahzamanian
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 finit…
The pro-nilpotent group topology on a free group
J. Almeida, M. H. Shahzamanian, B. Steinberg
In this paper, we work on the pro-nilpotent group topology of a free group. First we investigate the closure of the product of finitely many subgroups of a free group in the pro-ni…
Representations of relatively free profinite semigroups, irreducibility, and order primitivity
J. Almeida, O. Klíma
We establish that, under certain closure assumptions on a pseudovariety of semigroups, the corresponding relatively free profinite semigroups freely generated by a non-singleton fi…
Pointlike reducibility of pseudovarieties of the form
J. C. Costa, C. Nogueira, M. L. Teixeira
In this paper, we investigate the reducibility property of semidirect products of the form relatively to (pointlike) systems of equations of the form …
Random walks on semaphore codes and delay de Bruijn semigroups
John Rhodes, Anne Schilling, Pedro V. Silva
We develop a new approach to random walks on de Bruijn graphs over the alphabet through right congruences on , defined using the natural right action of . A major rol…
A geometric interpretation of the Schützenberger group of a minimal subshift
J. Almeida, A. Costa
The first author has associated in a natural way a profinite group to each irreducible subshift. The group in question was initially obtained as a maximal subgroup of a free profin…
Reducibility of pointlike problems
J. Almeida, J. C. Costa, M. Zeitoun
We show that the pointlike and the idempotent pointlike problems are reducible with respect to natural signatures in the following cases: the pseudovariety of all finite semigroups…
Factoriality and the Pin-Reutenauer procedure
J. Almeida, J. C. Costa, M. Zeitoun
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 semigr…
Hexagonal Projected Symmetries
Juliane F. Oliveira, Sofia S. B. S. D. Castro, Isabel S. Labouriau
In the study of pattern formation in symmetric physical systems a 3-dimensional structure in thin domains is often modelled as 2-dimensional one. We are concerned with functions in…