Subelliptic pseudo-differential operators and Fourier integral operators on compact Lie groups (funded by the Ghent Analysis and PDE Center)
Project: PhD Thesis. Main topic: Subelliptic pseudo-differential operators and Fourier integral operators on compact Lie groups (2019-2023)
Supported by the Ghent Analysis and PDE Center
Website of the center: Visit the GAPDE Center. Promotor: Prof. Dr. Michael Ruzhansky. Publications related to this project are available on the website: Publications (2019-2023).
About the project: This dissertation develops a pseudo-differential operator theory adapted to an arbitrary Hörmander sub-Laplacian on compact Lie groups, or, in other words, associated with an arbitrary sub-Riemannian structure over a compact Lie group. By following recent developments in the field, namely, the global quantisation theories of pseudo-differential operators, one in compact Lie groups (due to M. Ruzhansky and V. Turunen) and the other one on graded Lie groups (as developed by M. Ruzhansky and V. Fischer), this dissertation solves several open problems that arose in this setting in (1) harmonic analysis, (2) spectral theory, (3) control theory, and (4) PDE, considered as different but related areas of modern mathematics. The problems considered here include: (i) the Lp-theory of these pseudo-differential classes in the sub-Riemannian setting and in the setting of graded Lie groups, (ii) the spectral and qualitative properties of operators in ideals of compact operators, (iii) the extension of the theory of oscillating singular integrals due to Fefferman and Stein on compact and on graded Lie groups, (iv) an analysis of the dyadic maximal function on graded Lie groups and (v) an extensive number of applications to the well-posedness of diffusions models on compact Lie groups including applications of our pseudo-differential techniques to control theory.
Institutions: Ghent University, Belgium.
Keywords: Microlocal Analysis, Geometric Analysis.