Ara es mostren els items 12-31 de 31

    • On the geometry of the generalized partial realization problem 

      Baragaña, Itziar; Puerta Sales, Ferran; Puerta Coll, Xavier; Zaballa, Ion (2010-09)
      Article
      Accés restringit per política de l'editorial
      The geometry of the set of generalized partial realizations of a finite nice sequence of matrices is studied. It is proved that this set is a stratified manifold, the dimension of their strata is computed and its connection ...
    • On the geometry of the solutions of the cover problem 

      Puerta Sales, Ferran; Puerta Coll, Xavier; Zaballa, Ion (2003)
      Article
      Accés obert
      For a given system (A;B) and a subspace S, the Cover Problem consits of ¯nding all (A;B)-invariant subspaces containing S. For controllable systems, the set of these subspaces can be suitably strati¯ed. In this paper, ...
    • On the parametrization of the controllability pairs of a controllable subspaces of a controllable pair 

      Puerta Sales, Ferran; Puerta Coll, Xavier; Zaballa, Ion (2004)
      Article
      Accés obert
      Given a controllable linear control system defined by a pair of constant matrices (A,B), the set of controllability subspaces is a stratified submanifold of the set of (A,B)-invariant subspaces. We parametrize each strata ...
    • On the parametrization of the controllability subspaces of a controllable pair 

      Puerta Sales, Ferran; Puerta Coll, Xavier; Zaballa, Ion (2003)
      Article
      Accés obert
      Given a controllable linear control system defined by a pair of constant matrices (A;B), the set of controllability subspaces is an stratified submanifold of the set of (A;B)-invariant subspaces. We parameterize each ...
    • On the perturbation of bimodal systems 

      Puerta Coll, Xavier; Puerta Sales, Ferran (Servicio de publicaciones de la UPV, 2010)
      Comunicació de congrés
      Accés obert
      Given a bimodal system de¯ned by the equations ½ x_ (t) = A1x(t) + Bu(t) if ctx(t) · 0 x_ (t) = A2x(t) + Bu(t) if ctx(t) ¸ 0 (1) where B 2Mn;m and Ai 2Mn, i = 1; 2, are such that A1;A2 coincide on the hyper- plane V ...
    • On the stratifications of the set of $(A,B)$-invariant and controllability subspaces 

      Puerta Sales, Ferran; Puerta Coll, Xavier (2001)
      Article
      Accés obert
    • Output Maximal Dimension for the Disturbance Decoupling Problem 

      Puerta Sales, Ferran; Puerta Coll, Xavier; Zaballa, Ion (2001)
      Article
      Accés obert
      Given a linear time invariant system with a disturbance we describe a method of finding the maximal dimensional output for a generic Disturbance Decoupling problem.
    • Perturbation of quadrics 

      Clotet Juan, Josep; Magret Planas, Maria dels Dolors; Puerta Coll, Xavier (2000)
      Article
      Accés obert
      The aim of this paper is to study what happens when a slight perturbation affects the coefficients of a quadratic equation defining a variety (a quadric) in R^n. Structurally stable quadrics are those a small perturbation ...
    • Quadern de pràctiques amb Maple V 

      Bruguera Padró, Maria Montserrat; Ferrer Biosca, Alberto; Guillamon Grabolosa, Antoni; Mitjana Riera, Margarida; Pañella Brustenga, Francisco de Asís; Puerta Coll, Xavier; Rodríguez Jordana, Juan; Serrat Piè, Carles (Universitat Politècnica de Catalunya, 1999)
      Apunts
      Accés obert
    • Simultaneous versal deformations of endomorphisms and invariant subspaces 

      Compta Creus, Albert; Helmke, Uwe; Peña Carrera, Marta; Puerta Coll, Xavier (2004)
      Article
      Accés obert
      We study the set M of pairs (f; V ), defined by an endomorphism f of Fn and a d- dimensional f–invariant subspace V . It is shown that this set is a smooth manifold that defines a vector bundle on the Grassmann manifold. ...
    • Stability of (A,B)-invariant subspaces 

      Peña Carrera, Marta; Puerta Coll, Xavier; Puerta Sales, Ferran (2005)
      Article
      Accés obert
      Given a pair of matrices (A;B) we study the stability of their invariant subspaces from the geometry of the manifold of quadruples (A;B; S; F) where S is an (A;B)-invariant subspace and F is such that (A + BF)S ½ S. In ...
    • Stability of <math>(A, B)</math>-invariant subspaces 

      Puerta Sales, Ferran; Puerta Coll, Xavier (2003)
      Report de recerca
      Accés obert
      Given a pair of matrices (A,B) we study the stability of their invariant subspaces from a geometric point of view. The main tool is the manifold of quadruples((A;B); F; S) where S is an (A,B)-invariant subspace and F is ...
    • Stratification and bundle structure of the set of conditioned invariant subspaces in the general case 

      Ferrer Llop, Josep; Puerta Sales, Ferran; Puerta Coll, Xavier (2000)
      Article
      Accés obert
      We extend some known results about the smooth stratification of the set of conditioned invariant subspaces for a general pair $(C,A)\in\w C^n\times\w C^{n+m}$ without any assumption on the observability. More precisely ...
    • Stratification and bundle structure of the set of conditioned invariant subspaces in the general case 

      Ferrer Llop, Josep; Puerta Sales, Ferran; Puerta Coll, Xavier (2003)
      Article
      Accés obert
      We extend some known results about the smooth stratification of the set of conditioned invariant subspaces for a general pair $(C,A)\in\w C^n\times\w C^{n+m}$ without any assumption on the observability. More precisely ...
    • Stratification and bundle structure of the set of general (A,B)-invariant subspaces 

      Ferrer Llop, Josep; Puerta Sales, Ferran; Puerta Coll, Xavier (1998)
      Article
      Accés obert
      Given (A,B) in Hom(C^(n+m) C^n), we prove that the set of (A,B)-invariant subspaces having a fixed Brunovsky-Kronecker structure is a submanifold of the corresponding grassman manifold, and we compute its dimension. Also, ...
    • The geometry of the set of conditioned invariant flags 

      Puerta Coll, Xavier (1999)
      Working paper
      Accés obert
    • The topology of the set of conditioned invariant subspaces 

      Puerta Coll, Xavier; Helmke, Uwe (1999)
      Article
      Accés obert
      We consider the topology of the set of conditioned invariant subspaces of an observable pair $(C,A)$ of a fixed dimension. By fixing the observability indices of the restricted system, a stratification by finitely many ...
    • Versal deformations in generalized flag manifolds 

      Puerta Coll, Xavier (2004)
      Article
      Accés obert
      We find explicit miniversal deformations of flags in the generalized flag manifolds, with regard a natural equivalence relation defined by the group action that keeps fixed the reference flag.
    • Versal deformations in orbit spaces 

      Puerta Sales, Ferran; Puerta Coll, Xavier; Tarragona Romero, Sonia (2003)
      Article
      Accés obert
      Given an orbit space $M/\Gamma$ and an equivalence relation defined in it by means of the action of a group $G$, we obtain a miniversal deformation of an orbit through a miniversal deformation in $M$ with regard to a ...
    • Versal deformations in orbit spaces of matrices 

      Puerta Sales, Ferran; Puerta Coll, Xavier; Tarragona Romero, Sonia (2002)
      Article
      Accés obert
      Given an orbit space of matrices $M/\Gamma$ and an equivalence relation defined in it by means of the action of a group $G$, we obtain a miniversal deformation of an orbit through a minivesal deformation in $M$ with regard ...