Now showing items 1-8 of 8

  • Adiabatic invariant of the harmonic oscillator, complex matching and resurgence 

    Bonet Revés, Carles; Sauzin, D.; Martínez-Seara Alonso, M. Teresa; València Guitart, Marta (1997)
    Article
    Open Access
    The linear oscillator equation with a frequency depending slowly on time is used to test a method to compute exponentially small quantities. This work present the matching method in the complex plane as a tool to obtain ...
  • A singular initial value problem to construct density-equalizing maps 

    Avinyó Andrés, Albert; Solà-Morales Rubió, Joan de; València Guitart, Marta (2011-12)
    Article
    Restricted access - publisher's policy
    The diffusion-based algorithm to produce density-equalizing maps interprets diffusion as an advection process. This algorithm uses the dynamics of a flow that is defined by an initial value problem that turns out to be ...
  • A singular initial value problem to construct density-equalizing maps 

    Avinyó Andrés, Albert; Solà-Morales Rubió, Joan de; València Guitart, Marta (2011-05)
    External research report
    Open Access
    The diffusion-based algorithm to produce density-equalizing maps interprets diffusion as an advection process. This algorithm uses the dynamics of a flow that is defined by an initial value problem that turns out to be ...
  • Bounded solutions of some nonlinear elliptic equations in cylindrical domains 

    Calsina Ballesta, Ángel; Solà-Morales Rubió, Joan de; València Guitart, Marta (1997)
    Article
    Open Access
    The existence of a (unique) solution of the second order semilinear elliptic equation $$ \sum^{n}_{i,j=0}a_{ij}(x)u_{x_{i}x_{j}}+f(\nabla u,u,x)=0 $$ with $x=(x_{0},x_{1},\dots, x_{n})\in (s_{0},\infty )\times \Omega '$, ...
  • Diffeomorphisms with Given Jacobians involving the Heat Equation 

    Avinyó Andrés, Albert; Solà-Morales Rubió, Joan de; València Guitart, Marta (2000-12)
    Article
    Open Access
  • EQUACIONS DIFERENCIALS 2 (Examen 2n quadrim) 

    València Guitart, Marta (Universitat Politècnica de Catalunya, 2007-05-21)
    Exam
    Restricted access to the UPC academic community
  • On maps with given jacobians involving the heat equation 

    Avinyó Andrés, Albert; Solà-Morales Rubió, Joan de; València Guitart, Marta (2000)
    Article
    Open Access
    In this paper we presennt and analyze two new algorithms to construct a smooth diffeomorphism of a domain with prescribed jacobian function. The first one is free from any restriction on the boundary, while the second ...
  • On the diffusion algorithm for density-equalizing maps with piecewise constant initial data 

    Avinyó Andrés, Albert; Solà-Morales Rubió, Joan de; València Guitart, Marta (2012-07-15)
    Article
    Restricted access - publisher's policy
    We mathematically analyze the diffusion-based algorithm to produce maps with a given Jacobian, introduced independently by M. T. Gastner and M. E. J. Newman (2004) and ourselves (2003), but in particular cases where the ...