Ara es mostren els items 81-100 de 109

    • New contributions to the Hamiltonian and Lagrangian contact formalisms for dissipative mechanical systems and their symmetries 

      Gaset Rifà, Jordi; Gràcia Sabaté, Francesc Xavier; Muñoz Lecanda, Miguel Carlos; Rivas Guijarro, Xavier; Román Roy, Narciso (2020-06-01)
      Article
      Accés obert
      We provide new insights into the contact Hamiltonian and Lagrangian formulations of dissipative mechanical systems. In particular, we state a new form of the contact dynamical equations, and we review two recently presented ...
    • 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 (2011-02)
      Article
      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 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 k-symplectic, k-cosymplectic and multisymplectic formalisms of classical field theories 

      Román Roy, Narciso; Rey, Angel M.; Salgado, Modesto; Vilariño, Silvia (American Institute of Mathematical Sciences, 2011-03)
      Article
      Accés restringit per política de l'editorial
      The objective of this work is twofold: First, we analyze the relation between the k-cosymplectic and the k-symplectic Hamiltonian and Lagrangian formalisms in classical eld theories. In particular, we prove the equivalence ...
    • On the k-symplectic, k-cosymplectic and multisymplectic formalisms of classical field theories 

      Román Roy, Narciso; Rey, Angel M.; Salgado, Modesto; Vilariño, Silvia (2007-05-31)
      Article
      Accés obert
      The objective of this work is twofold: First, we analyze the relation between the kcosymplectic and the k-symplectic Hamiltonian and Lagrangian formalisms in classical field theories. In particular, we prove the equivalence ...
    • 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 $J^3\pi$. ...
    • Origen y desarrollo histórico del cálculo infinitesimal 

      Muñoz Lecanda, Miguel Carlos; Román Roy, Narciso (Edicions UPC, 1999)
      Llibre
      Accés restringit a la comunitat UPC
      Esta obra intenta dar una visión de la evolución histórica del cálculo infinitesimal: Los problemas originales en el siglo XVII, la aportación realizada por Newton y Leibnitz que consistió fundamentalmente en efectuar una ...
    • Reduction and reconstruction of multisymplectic Lie systems 

      de Lucas Araujo, Javier; Gràcia Sabaté, Francesc Xavier; Ribas León, Xavier; Román Roy, Narciso; Vilariño Fernández, Silvia (Institute of Physics (IOP), 2022-07-22)
      Article
      Accés obert
      A Lie system is a non-autonomous system of first-order ordinary differential equations describing the integral curves of a non-autonomous vector field taking values in a finite-dimensional real Lie algebra of vector fields, ...
    • Reduction of polysymplectic manifolds 

      Román Roy, Narciso; Marrero González, Juan Carlos; Salgado Seco, Modesto; Vilariño, Silvia (2013-06-06)
      Report de recerca
      Accés obert
      The aim of this paper is to generalize the classical Marsden- Weinstein reduction procedure for symplectic manifolds to polysymplectic manifolds in or der to obtain quotient manifolds which in- herit the polysymplectic ...
    • Reduction of polysymplectic manifolds 

      Marrero, Juan Carlos; Román Roy, Narciso; Salgado Seco, Modesto; Vilariño, Silvia (2015-02-06)
      Article
      Accés obert
      The aim of this paper is to generalize the classical Marsden-Weinstein reduction procedure for symplectic manifolds to polysymplectic manifolds in order to obtain quotient manifolds which inherit the polysymplectic structure. ...
    • 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.
    • Skinner-Rusk formalism for optimal control 

      Barbero Liñán, María; Echeverría Enríquez, Arturo; Martín de Diego, David; Muñoz Lecanda, Miguel Carlos; Román Roy, Narciso (2006-12)
      Article
      Accés obert
      In 1983, the dynamics of a mechanical system was represented by a first-order system on a suitable phase space by R. Skinner and R. Rusk. The corresponding unified formalism developed for optimal control systems allows us ...
    • Skinner-Rusk unified formalism for optimal control systems and applications 

      Barbero Liñán, María; Echeverría Enríquez, Arturo; Martín de Diego, David; Muñoz Lecanda, Miguel Carlos; Román Roy, Narciso (2007-05-15)
      Article
      Accés obert
      A geometric approach to time-dependent optimal control problems is proposed. This formulation is based on the Skinner and Rusk formalism for Lagrangian and Hamiltonian systems. The corresponding unified formalism developed ...
    • 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 ...
    • Sobre las interacciones fundamentales, las partículas elementales y las teorías de campos 

      Román Roy, Narciso (Escola Tècnica Superior d'Enginyers de Telecomunicació de Barcelona, 1997)
      Article
      Accés obert
    • Some properties of multisymplectic manifolds 

      Román Roy, Narciso (Springer, 2019-10-01)
      Capítol de llibre
      Accés restringit per política de l'editorial
      This lecture is devoted to review some of the main properties of multisymplectic geometry. In particular, after reminding the standard definition of multisymplectic manifold, we introduce its characteristic submanifolds, ...
    • 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 ...
    • Structural aspects of Hamilton–Jacobi theory 

      Cariñena Marzo, José F.; Gràcia Sabaté, Francesc Xavier; Marmo, Giuseppe; Martínez Fernandez, Eduardo; Muñoz Lecanda, Miguel Carlos; Román Roy, Narciso (2016-02-01)
      Article
      Accés obert
      In our previous papers [11, 13] we showed that the Hamilton–Jacobi problem can be regarded as a way to describe a given dynamics on a phase space manifold in terms of a family of dynamics on a lower-dimensional manifold. ...
    • 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 ...