{ "id": "1402.1591", "version": "v1", "published": "2014-02-07T10:22:35.000Z", "updated": "2014-02-07T10:22:35.000Z", "title": "Recent progress in smoothing estimates for evolution equations", "authors": [ "Michael Ruzhansky", "Mitsuru Sugimoto" ], "comment": "13 pages", "journal": "in Progress in Partial Differential Equations, pp. 287-302, Springer Proceedings in Mathematics & Statistics, Vol. 44, 2013", "doi": "10.1007/978-3-319-00125-8_13", "categories": [ "math.AP" ], "abstract": "This paper is a survey article of results and arguments from several of authors' papers, and it describes a new approach to global smoothing problems for dispersive and non-dispersive evolution equations based on ideas of comparison principle and canonical transforms. For operators $a(D_x)$ of order $m$ satisfying the dispersiveness condition $\\nabla a(\\xi)\\neq0$, a range of smoothing estimates is established. Especially, time-global smoothing estimates for the operator $a(D_x)$ with lower order terms are the benefit of our new method. These estimates are known to fail for general non-dispersive operators. For the case when the dispersiveness breaks, we suggest a modification of the smoothing estimate. It is equivalent to the usual estimate in the dispersive case and is also invariant under canonical transformations for the operator $a(D_x)$. Moreover, it does continue to hold for a variety of non-dispersive operators $a(D_x)$, where $\\nabla a(\\xi)$ may become zero on some set. It is interesting that this method allows us to carry out a global microlocal reduction of equations to the translation invariance property of the Lebesgue measure.", "revisions": [ { "version": "v1", "updated": "2014-02-07T10:22:35.000Z" } ], "analyses": { "keywords": [ "lower order terms", "global microlocal reduction", "translation invariance property", "dispersiveness condition", "time-global smoothing estimates" ], "tags": [ "journal article" ], "note": { "typesetting": "TeX", "pages": 13, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2014arXiv1402.1591R" } } }