1,721,018 research outputs found

    Symmetry and convexity of level sets of solutions to Deltainftyu+f(u)=0Delta_infty u+f(u)=0

    No full text
    We consider the equation −infinity-Laplacian(u) = f(u) in a domain Omega with zero Dirichlet condition. where f is a nonnegative continuous function. We investigate whether the solutions to this equation inherit geometrical properties from the domain. We obtain results concerning convexity of level sets and symmetry of solutions

    Isolated singularities of solutions to the equation hboxdiv(a(Du)Du)=0hbox{div}(a(|Du|)Du)=0 in the plane

    No full text
    We study the polar singularities of solutions to equations of the form div(a(Du)Du)=0div(a(|Du|)Du)=0 in the plane. We assume a degenerate (and singular) ellipticity condition which includes the p-Laplacian as particular case. We represent the complex gradient of the solutions around a non-removable polar singularity z0z_0 in terms of a series expansion of a quasi conformal mapping H. The analysis of the asymptotic behavior of H gives power estimates from above and below for |Du| and we also obtain an upper bound for the index of Du in z0z_0, depending on the rate of growth of |Du|

    A lower bound for the gradient of inftyinfty-harmonic functions

    No full text
    We establish a lower bound for the gradient of the solution to infinity-Laplace equation in a strongly star-shaped annulus with capacity type boundary conditions. The proof involves properties of the radial derivative of the solution, so that starshapedness of level sets easily follows

    An approximate Gidas-Ni-Nirenberg theorem

    No full text
    We study positive solutions uu to Δu+f(u)=0\Delta u+f(u)=0 in Ω\Omega, u=0u=0 on Ω\partial\Omega, and we address the following question: if Ω\Omega is a small perturbation of a ball, is uu a small perturbation of a radially symmetric function? We prove two theorems which give an affirmative answer under different assumptions on the non-linearity ff and on the topologies in which perturbations are considered

    Volume bounds of inclusions from physical EIT measurements

    No full text
    We derive estimates on the volume of an unknown inclusion in an electrically conducting body from current and voltage measurements at the boundary. We adopt the so-called complete model of electrical impedance tomography
    corecore