Measure density and extension of Besov and Triebel-Lizorkin functions

Toni Heikkinen, Lizaveta Ihnatsyeva, Heli Tuominen

We show that a domain is an extension domain for a Hajłasz-Besov or for a Hajłasz-Triebel-Lizorkin space if and only if it satisfies a measure density condition. We use a modificat…