Now showing items 1-20 of 66

  • 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 (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 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 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 ...
  • 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
  • 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 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
    Restricted access - publisher's policy
    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; 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 ...
  • 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 ...
  • 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 ...
  • Formulación geométrica de las teorias Gauge y de Yang-Mills 

    Rivas Guijarro, Xavier (Universitat Politècnica de Catalunya, 2014-07)
    Bachelor thesis
    Open Access
    Este trabajo presenta todas las herramientas propias de la geometría diferencial necesarias para poder describir adecuadamente las teorías gauge y en particular las ecuaciones de Yang-Mills. Concretamente, el trabajo empieza ...
  • 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