Now showing items 13-24 of 150

    • A summary on symmetries and conserved quantities of autonomous Hamiltonian systems 

      Román Roy, Narciso (AMER INST MATHEMATICAL SCIENCES-AIMS, 2020)
      Article
      Open Access
      A complete geometric classification of symmetries of autonomous Hamiltonian systems is established; explaining how to obtain their associated conserved quantities in all cases. In particular, first we review well-known ...
    • Quadratic planar differential systems with algebraic limit cycles via quadratic plane Cremona maps 

      Alberich Carramiñana, Maria; Ferragut Amengual, Antoni Manel; Llibre Saló, Jaume (Elsevier, 2021)
      Article
      Open Access
      In this paper we study the action of planar birational transformations, also known as plane Cremona maps, on quadratic planar differential systems. We provide geometrical characterizations of when a quadratic system is ...
    • The minimal tjurina number of irreducible germs of plane curve singularities 

      Alberich Carramiñana, Maria; Almirón Cuadros, Patricio; Blanco Fernández, Guillem; Melle Hernández, Alejandro (2021-01-01)
      Article
      Open Access
      In this paper we give a positive answer to a question of Dimca and Greuel about the quotient between the Milnor and the Tjurina numbers for any irreducible germ of plane curve singularity. This result is based on a closed ...
    • SAQ: semi-algebraic quartet reconstruction 

      Casanellas Rius, Marta; Fernández Sánchez, Jesús; Garrote López, Marina (2021-01-01)
      Article
      Open Access
      We present the phylogenetic quartet reconstruction method SAQ (Semi-Algebraic Quartet reconstruction). SAQ is consistent with the most general Markov model of nucleotide substitution and, in particular, it allows for rate ...
    • An overview of the Hamilton–Jacobi theory: the classical and geometrical approaches and some extensions and applications 

      Román Roy, Narciso (Multidisciplinary Digital Publishing Institute (MDPI), 2021-01-01)
      Article
      Open Access
      This work is devoted to review the modern geometric description of the Lagrangian and Hamiltonian formalisms of the Hamilton–Jacobi theory. The relation with the “classical” Hamiltonian approach using canonical transformations ...
    • Higher-order contact mechanics 

      De León, Manuel; Gaset Rifà, Jordi; Lainz Valcázar, Manuel; Muñoz Lecanda, Miguel Carlos; Román Roy, Narciso (Elsevier, 2021-02-01)
      Article
      Restricted access - publisher's policy
      We present a complete theory of higher-order autonomous contact mechanics, which allows us to describe higher-order dynamical systems with dissipation. The essential tools for the theory are the extended higher-order tangent ...
    • Constructing Turing complete Euler flows in dimension 3 

      Cardona Aguilar, Robert; Miranda Galcerán, Eva; Peralta-Salas, Daniel; Presas, Francisco (2021-05-11)
      Article
      Open Access
      Can every physical system simulate any Turing machine? This is a classical problem which is intimately connected with the undecidability of certain physical phenomena. Concerning fluid flows, Moore asked in [15] if ...
    • Distance to the stochastic part of phylogenetic varieties 

      Casanellas Rius, Marta; Fernández Sánchez, Jesús; Garrote López, Marina (2021-05)
      Article
      Restricted access - publisher's policy
      Modelling the substitution of nucleotides along a phylogenetic tree is usually done by a hidden Markov process. This allows to define a distribution of characters at the leaves of the trees and one might be able to obtain ...
    • Divisors of expected Jacobian type 

      Álvarez Montaner, Josep; Planas Vilanova, Francesc d'Assís (2021)
      Article
      Open Access
      Divisors whose Jacobian ideal is of linear type have received a lot of attention recently because of its connections with the theory of D-modules. In this work we are interested on divisors of expected Jacobian type, that ...
    • Current distributions in wide YBCO tapes 

      Carrera, Miquel; Granados García, Xavier; Amorós Torrent, Jaume; Puig Molina, Teresa; Obradors Berenguer, Xavier (Elsevier, 2012)
      Article
      Open Access
      The need of a better mechanical behaviour and the stabilization of coated conductors for applications, as Magnets, cables or Fault Current Limiters, has motivated the lamination of tapes with stainless steel or copper ...
    • Current distribution in HTSC tapes obtained by inverse problem calculation 

      Carrera, Miquel; Granados García, Xavier; Amorós Torrent, Jaume; Maynou Gil, Roger; Puig Molina, Teresa; Obradors Berenguer, Xavier (Institute of Physics (IOP), 2010)
      Article
      Open Access
      The development of SC devices based on HTSC tapes requires a deep knowledge of the current distribution in both pre-saturation and post-saturation regimes. Magnetic measurements have shown the possibilities ...
    • Computation of critical current in artificially structurated bulk samples from Hall measurements 

      Carrera, Miquel; Granados García, Xavier; Amorós Torrent, Jaume; Maynou Gil, Roger; Puig Molina, Teresa; Obradors Berenguer, Xavier (Institute of Physics (IOP), 2008)
      Article
      Open Access
      High-temperature superconducting artificially structured bulk samples, such as bulks with slanted drills or welds of different pieces along the c-axis with holes drilled in different asymmetric positions, ...