On the equivalence of fractional-order Sobolev semi-norms
Norbert Heuer
J. Math. Anal. Appl. 417 (2), 505-518, 2014.
We present various results on the equivalence and mapping properties under affine
transformations of fractional-order Sobolev norms and semi-norms of orders between
zero and one. Main results are mutual estimates of the three semi-norms of
Sobolev-Slobodeckij, interpolation and quotient space types.
In particular, we show that the former two are uniformly equivalent under
affine mappings that ensure shape regularity of the domains under consideration.