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
34 papers · 1 filter
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…
Is there switching without suspended horseshoes?
Alexandre Rodrigues
In general, infinite switching behaviour near networks is associated with the existence of suspended horseshoes. Trajectories that realize switching lie within these transitive set…
Rényi entropy and the thermodynamic stability of black holes
Viktor G. Czinner, Hideo Iguchi
Thermodynamic stability of black holes, described by the Rényi formula as equilibrium compatible entropy function, is investigated. It is shown that within this approach, asymptoti…
A local non-negative initial data scalar characterisation of the Kerr solution
Alfonso García-Parrado Gómez-Lobo
For any vacuum initial data set, we define a local, non-negative scalar quantity which vanishes at every point of the data hypersurface if and only if the data are {\em Kerr initia…
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…
Hard Lefschetz Theorem for Vaisman manifolds
Beniamino Cappelletti-Montano, Antonio De Nicola, Juan Carlos Marrero +1
We establish a Hard Lefschetz Theorem for the de Rham cohomology of compact Vaisman manifolds. A similar result is proved for the basic cohomology with respect to the Lee vector fi…
Limit cycles for a class of equivariant systems without infinite equilibria
Isabel S. Labouriau, Adrian C. Murza
We analyze the dynamics of a class of -equivariant differential equations on the plane, depending on 4 real parameters. This study is the generalisation to $\mathb…
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…
Dirichlet principal eigenvalue comparison theorems in geometry with torsion
Ana Cristina Ferreira, Isabel Salavessa
We describe min-max formulas for the principal eigenvalue of a -drift Laplacian defined by a vector field on a geodesic ball of a Riemannian manifold . Then we derive com…
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…
A non-Sasakian Lefschetz K-contact manifold of Tievsky type
Beniamino Cappelletti-Montano, Antonio De Nicola, Juan Carlos Marrero +1
We find a family of five dimensional completely solvable compact manifolds that constitute the first examples of -contact manifolds which satisfy the Hard Lefschetz Theorem and…
Crossover to the stochastic Burgers equation for the WASEP with a slow bond
Tertuliano Franco, Patricia Gonçalves, Marielle Simon
We consider the weakly asymmetric simple exclusion process in the presence of a slow bond and starting from the invariant state, namely the Bernoulli product measure of parameter $…
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…
Numerical semigroups with a given set of pseudo-Frobenius numbers
M. Delgado, P. A. García-Sánchez, A. M. Robles-Pérez
The pseudo-Frobenius numbers of a numerical semigroup are those gaps of the numerical semigroup that are maximal for the partial order induced by the semigroup. We present a proced…
On Equilibrium States for Partially Hyperbolic Horseshoes
Isabel Rios, Jaqueline Siqueira
We prove existence and uniqueness of equilibrium states for a family of partially hyperbolic systems, with respect to Holder continuous potentials with small variation. The family…
Clustering of extreme events created by multiple correlated maxima
Davide Azevedo, Ana Cristina Moreira Freitas, Jorge Milhazes Freitas +1
We consider stochastic processes arising from dynamical systems by evaluating an observable function along the orbits of the system. The novelty is that we will consider observable…
Compactified universal jacobian and the double ramification cycle
Bashar Dudin
Using the compactified universal jacobian over the moduli space of stable marked curves, we give an expression in terms of natural classes of the zero section of the compactified u…
A new approach to the Pontryagin maximum principle for nonlinear fractional optimal control problems
H. M. Ali, F. Lobo Pereira, S. M. A. Gama
In this paper, we discuss a new general formulation of fractional optimal control problems whose performance index is in the fractional integral form and the dynamics are given by…
Branes in the moduli space of framed instantons
Emilio Franco, Marcos Jardim, Simone Marchesi
In the physicist's language, a brane in a hyperkahler manifold is a submanifold which is either complex or lagrangian with respect to three Kahler structures of the ambient manif…