J. Lang

collaborators

2 papers

math.FA2025

Notes on Non-Compact Maps and the Importance of Bernstein Numbers

David E Edmunds, Jan Lang

In this review paper we study non-compact operators and embeddings between function spaces, highlighting interesting phenomena and the significance of Bernstein numbers. In particu…

math.FA2025

Quantitative Non-Compactness Properties of the Fourier Transform on Optimal Spaces

David E. Edmunds, Petr Gurka, Jan Lang

We establish that the Fourier transform $F : L^{p} (R^{d}) \to L^{p^{'}, p} (R^{d})$ , for $d \in N$ and $1 < p < 2$ , is not strictly singular, thereby confirming t…