2010/06/03 by Martin Costabel, Costabel, Martin, Alan McIntosh +3
Mathematics · #Advanced Harmonic Analysis Research #Advanced Mathematical Physics Problems #Nonlinear Partial Differential Equations
paper · doi:10.48550/arxiv.1006.0562
Suppose that Ω is the open region in ℝn above a Lipschitz graph and let d denote the exterior derivative on ℝn. We construct a convolution operator T which preserves support in Ω, is smoothing of order 1 on the homogeneous function spaces, and is a potential map in the sense that dT is the identity on spaces of exact forms with support in Ω. Thus if f is exact and supported in Ω, then there is a potential u, given by u=Tf, of optimal regularity and supported in Ω, such that du=f. This has implications for the regularity in homogeneous function spaces of the de Rham complex on Ω with or without boundary conditions. The operator T is used to obtain an atomic characterisation of Hardy spaces Hp of exact forms with support in Ω when n/(n+1)