{ "id": "0910.4991", "version": "v2", "published": "2009-10-26T21:52:22.000Z", "updated": "2009-11-07T08:27:20.000Z", "title": "On a maximum principle and its application to logarithmically critical Boussinesq system", "authors": [ "Taoufik Hmidi" ], "comment": "41 pages", "categories": [ "math.AP" ], "abstract": "In this paper we study a transport-diffusion model with some logarithmic dissipations. We look for two kinds of estimates. The first one is a maximum principle whose proof is based on Askey theorem concerning characteristic functions and some tools from the theory of $C_0$-semigroups. The second one is a smoothing effect based on some results from harmonic analysis and sub-Markovian operators. As an application we prove the global well-posedness for the two-dimensional Euler-Boussinesq system where the dissipation occurs only on the temperature equation and has the form $\\frac{\\DD}{\\log^\\alpha(e^4+\\DD)}$, with $\\alpha\\in[0,\\frac12]$. This result improves the critical dissipation $(\\alpha=0)$ needed for global well-posedness which was discussed in [15].", "revisions": [ { "version": "v2", "updated": "2009-11-07T08:27:20.000Z" } ], "analyses": { "keywords": [ "logarithmically critical boussinesq system", "maximum principle", "application", "askey theorem concerning characteristic functions", "global well-posedness" ], "note": { "typesetting": "TeX", "pages": 41, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2009arXiv0910.4991H" } } }