2 papers
math.FA2016
Strong ultra-regularity properties for positive elements in the twisted convolutions
Yuanyuan Chen
We show that positive elements with respect to the twisted convolutions, belonging to some ultra-test function space of certain order at origin, belong to the ultra-test function s…
math.FA2016
The Weyl product on quasi-Banach modulation spaces
Yuanyuan Chen, Joachim Toft, Patrik Wahlberg
We study the bilinear Weyl product acting on quasi-Banach modulation spaces. We find sufficient conditions for continuity of the Weyl product and we derive necessary conditions. Th…