Parabolic mean values and maximal estimates for gradients of temperatures

We aim to prove inequalities of the form | δk - λ (x, t) ∇k u (x, t) | ≤ C MR+- MD#, λ, k u (x, t) for solutions of frac(∂ u, ∂ t) = Δ u on a domain Ω = D × R+, where δ (x, t) is the parabolic distance of (x, t) to parabolic boundary of Ω, MR+- is the one-sided Hardy-Littlewood maximal operator in t...

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Bibliographic Details
Authors: Aimar, Hugo Alejandro, Gomez, Ivana Daniela, Iaffei, Bibiana Raquel
Format: article
Status:Published version
Publication Date:2008
Country:Argentina
Institution:Consejo Nacional de Investigaciones Científicas y Técnicas
Repository:CONICET Digital (CONICET)
Language:English
OAI Identifier:oai:ri.conicet.gov.ar:11336/84272
Online Access:http://hdl.handle.net/11336/84272
Access Level:Open access
Keyword:GRADIENT ESTIMATES
HEAT EQUATION
MAXIMAL OPERATORS
MEAN VALUE FORMULA
https://purl.org/becyt/ford/1.1
https://purl.org/becyt/ford/1
Description
Summary:We aim to prove inequalities of the form | δk - λ (x, t) ∇k u (x, t) | ≤ C MR+- MD#, λ, k u (x, t) for solutions of frac(∂ u, ∂ t) = Δ u on a domain Ω = D × R+, where δ (x, t) is the parabolic distance of (x, t) to parabolic boundary of Ω, MR+- is the one-sided Hardy-Littlewood maximal operator in the time variable on R+, MD#, λ, k is a Calderón-Scott type d-dimensional elliptic maximal operator in the space variable on the domain D in Rd, and 0 < λ < k < λ + d. As a consequence, when D is a bounded Lipschitz domain, we obtain estimates for the Lp (Ω) norm of δ2 n - λ (∇2, 1)n u in terms of some mixed norm ∫0∞ {norm of matrix} u (ṡ, t) {norm of matrix}Bpλ, p (D)p d t for the space Lp (R+, Bpλ, p (D)) with {norm of matrix} ṡ {norm of matrix}Bpλ, p (D) denotes the Besov norm in the space variable x and where ∇2, 1 = (∇2, frac(∂, ∂ t)).