Relations between Kondratiev spaces and refined localization Triebel-Lizorkin spaces
Markus Hansen, Benjamin Scharf, Cornelia Schneider
TL;DR
This work develops a sharp bridge between Kondratiev weighted Sobolev spaces and refined localization Triebel–Lizorkin spaces to translate boundary singularity regularity into Besov/Triebel–Lizorkin adaptivity scales. It proves that for suitable domains ${\mathcal{K}}^m_{m,p}(D)$ coincides with ${F}^{m,\text{rloc}}_{p,2}(D)$ and, more generally, establishes embeddings ${\mathcal{K}}^m_{a,p}(D)\hookrightarrow F^{m,\text{rloc}}_{\tau,2}(D)$ (and into $F^m_{\tau,2}(D)$) under precise conditions on $(m,a,p,\tau)$ and the domain’s singular set. Two complementary proofs are offered: a Hölder-inequality approach and a localization-based method, both aided by diffeomorphism invariance to extend results to polyhedral domains. The reverse embeddings are also analyzed, clarifying when refined localization spaces sit inside Kondratiev spaces. Collectively, these embeddings enable sharper predictions for convergence rates of adaptive wavelet and finite element schemes by aligning PDE regularity with appropriate adaptivity scales.
Abstract
We investigate the close relation between certain weighted Sobolev spaces (Kondratiev spaces) and refined localization spaces from introduced by Triebel [39,40]. In particular, using a characterization for refined localization spaces from Scharf [32], we considerably improve an embedding from Hansen [17]. This embedding is of special interest in connection with convergence rates for adaptive approximation schemes.
