Sökning: "pseudo-differential operators"

Visar resultat 1 - 5 av 8 avhandlingar innehållade orden pseudo-differential operators.

  1. 1. Propagation of singularities for pseudo-differential operators and generalized Schrödinger propagators

    Författare :Karoline Johansson; Joachim Toft; Anders Olofsson; Linnéuniversitetet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Banach spaces; Fourier; Generalized time-dependent Schrödinger equation; Micro-local; Modulation spaces; Non-tangential convergence; Pseudo-differential operators; Regularity; Wave-front sets; Banachrum; Fourier; Generaliserad tidsberoende Schrödinger ekvation; Icke-tangentiell konvergens; Mikrolokal; Modulationsrum; Pseudodifferentialoperatorer; Regularitet; Vågfrontsmängder; Mathematical analysis; Analys; Mathematics; Matematik;

    Sammanfattning : In this thesis we discuss different types of regularity for distributions which appear in the theory of pseudo-differential operators and partial differential equations. Partial differential equations often appear in science and technology. LÄS MER

  3. 2. Continuity and Positivity Problems in Pseudo-differential Calculus

    Författare :Joachim Toft; Matematik (naturvetenskapliga fakulteten); []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; funktionsanalys; fourieranalys; Serier; functional analysis; Fourier analysis; Series; Entropy.; Young s inequality; Twisted convolution; Schatten-von Neumann; Lower bounds; Weyl Calculus; Pseudo-differential Operqator; Continuity; Positivity;

    Sammanfattning : The paper deals with various positivity and continuity questions arising in the Weyl calculus of pseudo-differential operators. Let W be a symplectic vector space. LÄS MER

  4. 3. Infinite dimensional holomorphy in the ring of formal power series : partial differential operators

    Författare :Henrik Petersson; Andrei Khrennikov; Sean Dineen; Växjö universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Infinite dimensional holomorphy; Formal power series; Fourier-Borel transform; Paley-Wiener theorem; Fischer decomposition; Fischer pair; Fock space; Cauchy-Problem; Kergin operator; PDE-preserving; Pseudo-differential operators.; MATHEMATICS; MATEMATIK;

    Sammanfattning : We study holomorphy in the ring of formal power series in an infinite number of variables. Thus we restrict our study to (infinite dimensional) holomorphy on sequence spaces and we show that we obtain a rich theory without requiring any topological structure on the domain space. We make a comprehensive PDO-study for the spaces under consideration. LÄS MER

  5. 4. Continuity and compositions of operators with kernels in ultra-test function and ultra-distribution spaces

    Författare :Yuanyuan Chen; Joachim Toft; Nenad Teofanov; Linnéuniversitetet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Composition; modulation spaces; positivity; pseudo-differential operators; Schatten-von Neumann operators; twisted convolutions; ultra-distributions; Matematik; Mathematics;

    Sammanfattning : In this thesis we consider continuity and positivity properties of pseudo-differential operators in Gelfand-Shilov and Pilipović spaces, and their distribution spaces. We also investigate composition property of pseudo-differential operators with symbols in quasi-Banach modulation spaces. LÄS MER

  7. 5. Index theory in geometry and physics

    Författare :Magnus C H T Goffeng; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Index theory; Cyclic cohomology; Regularized index formulas; Toeplitz operators; Pseudo-differential operators; Quantum Hall effect; Toeplitz operators;

    Sammanfattning : This thesis contains three papers in the area of index theory and its applications in geometry and mathematical physics. These papers deal with the problems of calculating the charge deficiency on the Landau levels and that of finding explicit analytic formulas for mapping degrees of Hölder continuous mappings. LÄS MER