{ "id": "1809.06803", "version": "v1", "published": "2018-09-18T15:37:52.000Z", "updated": "2018-09-18T15:37:52.000Z", "title": "Approximate solutions of vector fields and an application to Denjoy-Carleman regularity of solutions of a nonlinear PDE", "authors": [ "Nicholas Braun Rodrigues", "Antonio V. da Silva Jr" ], "categories": [ "math.AP" ], "abstract": "In this paper we study microlocal regularity of a $\\mathcal{C}^2$ solution $u$ of the equation \\begin{equation*} u_t = f(x,t,u,u_x), \\end{equation*} where $f(x,t,\\zeta_0, \\zeta)$ is ultradifferentiable in the variables $(x,t)\\in \\mathbb{R}^{N} \\times \\mathbb{R}$ and holomorphic in the variables $(\\zeta_0,\\zeta) \\in \\mathbb{C} \\times \\mathbb{C}^{N}$. We proved that if $\\mathcal{C}^{\\mathcal{M}}$ is a regular Denjoy-Carleman class (including the quasianalytic case) then: \\begin{equation*} \\mathrm{WF}_\\mathcal{M} (u)\\subset \\mathrm{Char}(L^u), \\end{equation*} where $\\mathrm{WF}_\\mathcal{M}(u)$ is the Denjoy-Carleman wave-front set of $u$ and $\\mathrm{Char}(L^u)$ is the characteristic set of the linearized operator $L^u$: \\begin{equation*} L^u = \\dfrac{\\partial}{\\partial t} - \\sum_{j=1}^{N}\\frac{\\partial f}{\\partial\\zeta_j}(x,t,u,u_x)\\dfrac{\\partial}{\\partial x_j}. \\end{equation*}", "revisions": [ { "version": "v1", "updated": "2018-09-18T15:37:52.000Z" } ], "analyses": { "keywords": [ "nonlinear pde", "denjoy-carleman regularity", "vector fields", "approximate solutions", "application" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }