Ara es mostren els items 19-38 de 41

    • More insights into symmetries in multisymplectic field theories 

      Guerra IV, Arnoldo; Román Roy, Narciso (2023-02-01)
      Article
      Accés obert
      This work provides a general overview for the treatment of symmetries in classical field theories and (pre)multisymplectic geometry. The geometric characteristics of the relation between how symmetries are interpreted in ...
    • Morse theory and Floer homology 

      Brugués Mora, Joaquim (Universitat Politècnica de Catalunya, 2019-01)
      Projecte Final de Màster Oficial
      Accés obert
      Morse homology studies the topology of smooth manifolds by examining the critical points of a real-valued function defined on the manifold, and connecting them with the negative gradient of the function. Rather surprisingly, ...
    • Multicontact formulation for non-conservative field theories 

      de León Rodríguez, Manuel; Gaset Rifà, Jordi; Muñoz Lecanda, Miguel Carlos; Rivas Guijarro, Xavier; Román Roy, Narciso (Institute of Physics (IOP), 2023-01-13)
      Article
      Accés obert
      A new geometric structure inspired by multisymplectic and contact geometries, which we call multicontact structure, is developed to describe non-conservative classical field theories. Using the differential forms that ...
    • Multisymplectic unified formalism for Einstein-Hilbert gravity 

      Gaset Rifà, Jordi; Román Roy, Narciso (2018-03-01)
      Article
      Accés obert
      We present a covariant multisymplectic formulation for the Einstein-Hilbert model of General Relativity. As it is described by a second-order singular Lagrangian, this is a gauge field theory with constraints. The use of ...
    • New multisymplectic approach to the Metric-Affine (Einstein-Palatini) action for gravity 

      Gaset Rifà, Jordi; Román Roy, Narciso (American Institute of Mathematical Sciences, 2019-09-01)
      Article
      Accés obert
      We present a covariant multisymplectic formulation for the Einstein-Palatini (or Metric-Affine) model of General Relativity (without energy-matter sources). As it is described by a first-order affine Lagrangian (in the ...
    • On a kind of Noether symmetries and conservation laws in k-cosymplectic field theory 

      Marrero González, Juan Carlos; Román Roy, Narciso; Salgado, Modesto; Vilariño, Silvia (2010-09-15)
      Report de recerca
      Accés obert
      This paper is devoted to studying symmetries of certain kinds of k-cosymplectic Hamiltonian systems in first-order classical field theories. Thus, we introduce a particular class of symmetries and study the problem of ...
    • On the singular Weinstein conjecture and the existence of escape orbits for b-Beltrami fields 

      Miranda Galcerán, Eva; Oms, Cédric; Peralta-Salas, Daniel (2021-10-07)
      Report de recerca
      Accés obert
      Motivated by Poincare’s orbits going to infinity in the (restricted) three-body problem ´ (see [29] and [7]), we investigate the generic existence of heteroclinic-like orbits in a neighbourhood of the critical set of a ...
    • Order reduction, projectability and constrainsts of second-order field theories and higuer-order mechanics 

      Gaset Rifà, Jordi; Román Roy, Narciso (2016-12-01)
      Article
      Accés obert
      The consequences of the projectability of Poincar\'e-Cartan forms in a third-order jet bundle $J^3\pi$ to a lower-order jet bundle are analyzed using the constraint algorithm for the Euler-Lagrange equations in $J^3\pi$. ...
    • Remarks on multisymplectic reduction 

      Echeverría Enríquez, Arturo; Muñoz Lecanda, Miguel Carlos; Román Roy, Narciso (2018-06-01)
      Article
      Accés obert
      The problem of reduction of multisymplectic manifolds by the action of Lie groups is stated and discussed, as a previous step to give a fully covariant scheme of reduction for classical field theories with symmetries.
    • Rigidity of cotangent lifts and integrable systems 

      Mir Garcia, Pau; Miranda Galcerán, Eva (2020-05)
      Report de recerca
      Accés obert
      In this article we generalize a theorem by Palais on the rigidity ofcompact group actions to cotangent lifts. We use this result to prove rigidity forintegrable systems on symplectic manifolds including sytems with ...
    • Rigidity of group actions, cotangent lifts and integrable systems 

      Mir Garcia, Pau (Universitat Politècnica de Catalunya, 2020-07)
      Projecte Final de Màster Oficial
      Accés obert
      Realitzat a/amb:   GEOMVAP - Geometria de Varietats i Aplicacions. Grup de Recerca
      In this master thesis we generalize a theorem by Palais on the rigidity of compact group actions to cotangent lifts. We use this result to prove rigidity for integrable systems on symplectic manifolds including systems ...
    • Rigidity of hamiltonian actions on poisson manifolds 

      Miranda Galcerán, Eva; Tien Zung, Nguyen; Monnier, Philippe (2012)
      Article
      Accés restringit per política de l'editorial
    • Singular cotangent models and complexity in fluids with dissipation 

      Coquinot, Baptiste; Mir Garcia, Pau; Miranda Galcerán, Eva (2022-06-17)
      Report de recerca
      Accés obert
      In this article we analyze several mathematical models with singularities where the classical cotangent model is replaced by a b-cotangent model. We provide physical interpretations of the singular symplectic geometry ...
    • Sistemes dinàmics de contacte 

      Muñoz Checa, Daniel (Universitat Politècnica de Catalunya, 2022-07)
      Treball Final de Grau
      Accés obert
      Aquest treball de fi de grau presenta la geometria de contacte, una branca de la geometria diferencial que permet descriure geomètricament certs sistemes dinàmics com ara sistemes amb dissipació. Aquesta formulació permet ...
    • Skinner–Rusk formalism for k-contact systems 

      Gràcia Sabaté, Francesc Xavier; Rivas Guijarro, Xavier; Román Roy, Narciso (2022-02-01)
      Article
      Accés obert
      In previous papers, a geometric framework has been developed to describe non-conservative field theories as a kind of modified Lagrangian and Hamiltonian field theories. This approach is that of k-contact Hamiltonian ...
    • Some topics concerning the theory of singular dynamical systems 

      Román Roy, Narciso (2006-03-01)
      Article
      Accés obert
      Some subjects related to the geometric theory of singular dynamical systems are reviewed in this paper. In particular, the following two matters are considered: the theory of canonical transformations for presymplectic ...
    • Symmetries and conservation laws in the Gunther k-symplectic formalism of field theory 

      Román Roy, Narciso; Salgado, Modesto; Vilariño, Silvia (2007-03-12)
      Article
      Accés obert
      This paper is devoted to studying symmetries of k-symplectic Hamiltonian and Lagrangian first-order classical field theories. In particular, we define symmetries and Cartan symmetries and study the problem of ...
    • Symplectic structures with singularities 

      Planas Bahí, Arnau (Universitat Politècnica de Catalunya, 2015-10)
      Projecte Final de Màster Oficial
      Accés obert
      The main goal of the thesis is to classify some particular Poisson structures, called b-Poisson, following results of Guillemin-Miranda-Pirés and Radko. To understand these results, this thesis contains some chapters of ...
    • Symplectic toric manifolds, Delzant theorem and integrable sytems 

      Cardona Aguilar, Robert (Universitat Politècnica de Catalunya, 2017-07)
      Treball Final de Grau
      Accés obert
      En aquesta tesi estudiarem la relació entre les varietats simplèctiques tòriques i els sistemes integrables. Per això, presentem en primer lloc tots els preliminars necessaris de geometria simplèctica. Després presentem ...
    • The geometry and topology of contact structures with singularities 

      Miranda Galcerán, Eva; Oms, Cedric (2020-05-20)
      Report de recerca
      Accés obert
      In this article we introduce and analyze in detail singular contact structures, with an emphasis on $b^m$-contact structures, which are tangent to a given smooth hypersurface $Z$ and satisfy certain transversality conditions. ...