{ "id": "2006.10326", "version": "v1", "published": "2020-06-18T07:31:58.000Z", "updated": "2020-06-18T07:31:58.000Z", "title": "The square root of a parabolic operator", "authors": [ "El Maati Ouhabaz" ], "categories": [ "math.AP", "math.FA" ], "abstract": "Let L(t) = --div (A(x, t)$\\nabla$ x) for t $\\in$ (0, $\\tau$) be a uniformly elliptic operator with boundary conditions on a domain $\\Omega$ of R d and $\\partial$ = $\\partial$ $\\partial$t. Define the parabolic operator L = $\\partial$ + L on L 2 (0, $\\tau$, L 2 ($\\Omega$)) by (Lu)(t) := $\\partial$u(t) $\\partial$t + L(t)u(t). We assume a very little of regularity for the boundary of $\\Omega$ and assume that the coefficients A(x, t) are measurable in x and piecewise C $\\alpha$ in t for some $\\alpha$ > 1 2. We prove the Kato square root property for $\\sqrt$ L and the estimate $\\sqrt$ L u L 2 (0,$\\tau$,L 2 ($\\Omega$)) $\\approx$ $\\nabla$ x u L 2 (0,$\\tau$,L 2 ($\\Omega$)) + u H 1 2 (0,$\\tau$,L 2 ($\\Omega$)) + $\\tau$ 0 u(t) 2 L 2 ($\\Omega$) dt t 1/2. We also prove L p-versions of this result. Keywords: elliptic and parabolic operators, the Kato square root property, maximal regularity, the holomorphic functional calculus, non-autonomous evolution equations.", "revisions": [ { "version": "v1", "updated": "2020-06-18T07:31:58.000Z" } ], "analyses": { "keywords": [ "parabolic operator", "kato square root property", "holomorphic functional calculus", "non-autonomous evolution equations", "maximal regularity" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }