{ "id": "1510.05733", "version": "v1", "published": "2015-10-20T01:38:24.000Z", "updated": "2015-10-20T01:38:24.000Z", "title": "Ill-posedness of the Navier-Stokes and magneto-hydrodynamics systems", "authors": [ "Alexey Cheskidov", "Mimi Dai" ], "categories": [ "math.AP", "physics.flu-dyn" ], "abstract": "We demonstrate that the three dimensional incompressible magneto-hydrodynamics (MHD) system is ill-posed due to the discontinuity of weak solutions in a wide range of spaces. Specifically, we construct initial data which has finite energy and is small in certain spaces, such that any Leray-Hopf type of weak solution to the MHD system starting from this initial data is discontinuous at time $t=0$ in such spaces. An analogous result is also obtained for the Navier-Stokes equation which extends the previous result of ill-posedness in $\\dot B^{-1}_{\\infty,\\infty}$ by Cheskidov and Shvydkoy to spaces that are not necessarily critical. The region of the spaces where the norm inflation occurs almost touches $L^2$.", "revisions": [ { "version": "v1", "updated": "2015-10-20T01:38:24.000Z" } ], "analyses": { "subjects": [ "76D03", "35Q35" ], "keywords": [ "magneto-hydrodynamics systems", "ill-posedness", "weak solution", "construct initial data", "norm inflation occurs" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }