Now showing items 1-20 of 70

    • A normal form theorem for integrable systems on contact manifolds 

      Miranda Galcerán, Eva (2005)
      Article
      Open Access
      We present a normal form theorem for singular integrable systems on contact manifolds
    • Ampliación al espacio de una aplicación de la integración en el campo complejo para la solución de una cuestión de informática gráfica 

      Lerma Usero, Miguel Ángel (Institut d'Estadística de Catalunya, 1992)
      Article
      Open Access
      El teorema de los residuos de Cauchy sirve como base para un algoritmo que permite determinar la posición relativa de un punto respecto a una curva cerrada simple. La ampliación de este método al espacio tropieza con la ...
    • An extension problem for the CR fractional Laplacian 

      Frank, Rupert L.; González Nogueras, María del Mar; Monticelli, Dario D.; Tan, Jinggang (2015-01-01)
      Article
      Open Access
      We show that the conformally invariant fractional powers of the sub-Laplacian on the Heisenberg group are given in terms of the scattering operator for an extension problem to the Siegel upper halfspace. Remarkably, this ...
    • An extension problem for the CR fractional Laplacian 

      Frank, Rupert L.; González Nogueras, María del Mar; Monticelli, Dario D.; Tan, Jinggang (2013-12)
      External research report
      Open Access
      We show that the conformally invariant fractional powers of the sub-Laplacian on the Heisenberg group are given in terms of the scattering operator for an extension problem to the Siegel upper halfspace. Remarkably, this ...
    • An invitation to singular symplectic geometry 

      Miranda Galcerán, Eva; Delshams Valdés, Amadeu; Dempsey Bradell, Roisin Mary; Oms, Cedric; Planas Bahí, Arnau (2019)
      Article
      Open Access
      In this paper we analyze in detail a collection of motivating examples to consider bm-symplectic forms and folded-type symplectic structures. In particular, we provide models in Celestial Mechanics for every bm-symplectic ...
    • Coexistence stability in a four-member hypercycle with error tail through center manifold analysis 

      Farre, Gerard; Sardanyes, Josep; Guillamon Grabolosa, Antoni; Fontich Julia, Ernest (2017-09-09)
      Article
      Open Access
      Establishing the conditions allowing for the stable coexistence in hypercycles has been a subject of intensive research in the past decades. Deterministic, time-continuous models have indicated that, under appropriate ...
    • Constraint algorithm for k-presymplectic hamiltonian systems: application to singular field theories 

      Gràcia Sabaté, Francesc Xavier; Martín Grillo, Rubén; Román Roy, Narciso (World Scientific and Engineering Academy and Society (WSEAS), 2009-08-01)
      Article
      Open Access
      The k-symplectic formulation of field theories is specially simple, since only tangent and cotangent bundles are needed in its description. Its defining elements show a close relationship with those in the symplectic formulation ...
    • Constraint algorithm for singular field theories in the k-cosymplectic framework 

      Gràcia Sabaté, Francesc Xavier; Rivas Guijarro, Xavier; Román Roy, Narciso (American Institute of Mathematical Sciences, 2020-03-15)
      Article
      Restricted access - publisher's policy
      The aim of this paper is to develop a constraint algorithm for singular classical field theories in the framework of k-cosymplectic geometry. Since these field theories are singular, we need to introduce the notion of ...
    • Constraint algorithm for singular k-cosymplectic field theories 

      Rivas Guijarro, Xavier (Universitat Politècnica de Catalunya, 2015-10)
      Master thesis
      Open Access
      The main objective of this thesis is to develop a constraint algorithm for singular k-cosymplectic field theories.
    • Control del error de interpolación cúbica de la intersección de superficies parámetricas de forma libre 

      Olivencia, José; Quiroz, Luis (Universitat Politècnica de Catalunya, 2003)
      Article
      Open Access
      Se propone un método numérico de trazado capaz de producir un interpolante que aproxime la intersección de dos superficies con un error no mayor que una tolerancia dada. Conceptos de geometría diferencial son empleados ...
    • Cotangent bundle reduction with singularities 

      Rodríguez Olmos, Miguel Andrés (2010)
      Lecture
      Open Access
    • Curves and surfaces with constant nonlocal mean curvature: Meeting Alexandrov and Delaunay 

      Cabré Vilagut, Xavier; Fall, Mouhamed Moustapha; Solà-Morales Rubió, Joan de (2018-12-01)
      Article
      Open Access
      We are concerned with hypersurfaces of RN with constant nonlocal (or fractional) mean curvature. This is the equation associated to critical points of the fractional perimeter under a volume constraint. Our results are ...
    • Deformaciones miniversales de parejas de tensores de segundo orden 

      Clotet Juan, Josep; Magret Planas, Maria dels Dolors; Peña Carrera, Marta (Universidad de Sevilla, 2007-09)
      Conference report
      Open Access
      Consideramos en el espacio de parejas de tensores tension y deformacion la relacion de equivalencia que se corresponde con cambios de base ortonormales. Identificandolas con parejas de matrices cuadradas, podemos utilizar ...
    • Desingularizing b^m-symplectic structures 

      Miranda Galcerán, Eva (2015-12)
      External research report
      Open Access
      A 2n-dimensional Poisson manifold (M,¿) is said to be bm-symplectic if it is symplectic on the complement of a hypersurface Z and has a simple Darboux canonical form at points of Z which we will describe below. In this ...
    • Desingularizing b^m-symplectic structures 

      Miranda Galcerán, Eva; Guillemin, Victor; Weitsman, Jonathan (2017)
      Article
      Open Access
      A 2n-dimensional Poisson manifold (M,Π) is said to be bm-symplectic if it is symplectic on the complement of a hypersurface Z and has a simple Darboux canonical form at points of Z which we will describe below. In this ...
    • Differential Feedback of MIMO Channel Gram Matrices Based on Geodesic Curves 

      Sacristán Murga, Daniel; Pascual Iserte, Antonio (2010-12)
      Article
      Restricted access - publisher's policy
      This paper proposes a differential quantization strategy to be used in the feedback link of a multiple-input multiple-output (MIMO) communication system. This algorithm is applied to the channel Gram matrix using geodesic ...
    • Equivalence between the Hamiltonian and Lagrangian formalisms for constrained systems 

      Batlle Arnau, Carles; Gomis Torné, Joaquin; Pons Ràfols, Josep Maria; Román Roy, Narciso (1986-08)
      Article
      Open Access
      The equivalence between the Lagrangian and Hamiltonian formalism is studied for constraint systems. A procedure to construct the Lagrangian constraints from the Hamiltonian constraints is given. Those Hamiltonian constraints ...
    • Equivariant classification of bm-symplectic surfaces 

      Miranda Galcerán, Eva; Planas Bahí, Arnau (Springer, 2018-07-24)
      Article
      Open Access
      Inspired by Arnold’s classification of local Poisson structures [1] in the plane using the hierarchy of singularities of smooth functions, we consider the problem of global classification of Poisson structures on surfaces. ...
    • Estudi de les estructures geomètriques dels sistemes dinàmics d'ordre superior 

      Prieto Martínez, Pedro Daniel (Universitat Politècnica de Catalunya, 2011)
      Master thesis
      Open Access
      El formalisme unificat Lagrangià-Hamiltonià de R. Skinner i R. Rusk fou desenvolupat originalment per a sistemes dinàmics autònoms de la mecànica clàssica. Més recentment s'ha generalitzat per a sistemes mecànics no autònoms ...
    • Formulació relativista de les equacions de posicionament del sistema GPS 

      Moragues Albacar, Jaime (Universitat Politècnica de Catalunya, 2008-11-17)
      Master thesis (pre-Bologna period)
      Open Access