2006/12/11 by Michael Ruzhansky, Mitsuru Sugimoto, Ruzhansky, Michael +1
Mathematics · Physics and Astronomy · #35B65 #35J10 #35Q40 #35S30 #47G30 #Advanced Mathematical Physics Problems #Analysis of PDEs (math.AP) #FOS: Mathematics #Functional Analysis (math.FA) #Navier-Stokes equation solutions #Nonlinear Waves and Solitons
paper · pdf · doi:10.48550/arxiv.math/0612274
openalex publication_date 2006/12/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The paper describes a new approach to global smoothing problems for dispersive and non-dispersive evolution equations based on the global canonical transforms and the underlying global microlocal analysis. For this purpose, the Egorov-type theorem is established with canonical transformations in the form of a class of Fourier integral operators, and their weighted L2-boundedness properties are derived. This allows us to globally reduce general dispersive equations to normal forms in one or two dimensions. Then, several comparison principles are introduced to relate different smoothing estimates by comparing certain expressions involving their symbols. As a result, it is shown that the majority of smoothing estimates for different equations are equivalent to each other. Moreover, new estimates as well as several refinements of known results are obtained. The proofs are considerably simplified. A comprehensive analysis of smoothing estimates for dispersive and also non-dispersive equations with constant coefficients is presented. Applications are given to the detailed description of smoothing properties of the Schrodinger, relativistic Schrodinger, wave, Klein-Gordon, and other equations. Critical cases of some estimates and their relation to the trace estimates are discussed.