2020/04/08 by Jean-Yves Chemin, Isabelle Gallagher, Chemin, Jean-Yves +3
Mathematics · #35K55 #Advanced Mathematical Physics Problems #Analysis of PDEs (math.AP) #FOS: Mathematics #Navier-Stokes equation solutions #Nonlinear Partial Differential Equations
paper · pdf · doi:10.48550/arxiv.2004.03908
openalex publication_date 2020/04/08 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We study the radius of analyticity~R(t) in space, of strong solutions to systems of scale-invariant semi-linear parabolic equations. It is well-known that near the initial time,~R(t)t-\frac12 is bounded from below by a positive constant. In this paper we prove that~\liminft→ 0 R(t)t-\frac12= ∞, and assuming higher regularity for the initial data, we obtain an improved lower bound near time zero. As an application, we prove that for any global solution~u∈ C([0,∞); H\frac12(\R3)) of the Navier-Stokes equations, there holds~\liminft→ ∞ R(t)t-\frac12= ∞.