G. Bourdaud

activity

20182024

collaborators

3 papers

math.FA2024

The higher order chain rule in Sobolev spaces

Gérard Bourdaud

We establish the Faà di Bruno formula, in the sense of almost everywhere equality, for derivatives of the composed function $f \circ g$ , for all function $f : R \to R$ such…

math.FA2021

Szasz's theorem and its generalizations

Gérard Bourdaud

We establish the most general Szasz type estimates for homogeneous Besov and Lizorkin-Triebel spaces, and their realizations.

math.FA2018

Continuity of composition operators in Sobolev spaces

Gérard Bourdaud, Madani Moussai

We prove that all the composition operators $T_{f} (g) := f \circ g$ , which take the Adams-Frazier space $W_{p}^{m} \cap W ˙_{m p}^{1} (R^{n})$ to itself, are continuous mapping…