Sökning: "ultra-distributions"

Hittade 2 avhandlingar innehållade ordet ultra-distributions.

  1. 1. 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

  3. 2. Contributions to three problems in systems of differential and convolution equations

    Författare :Wojciech Abramczuk; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : We study three problems:PROBLEM A. Let P(D) be a matrix of partial differential operators with constant coefficient and U an open, convex and bounded set in Rn. Consider the system P(D)u = f where f lies in a Sobolev space on Rn and satisfies the compatibility conditions in U. LÄS MER