Sökning: "twisted convolutions"

Hittade 2 avhandlingar innehållade orden twisted convolutions.

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. 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