Characterization of traces of smooth functions on Ahlfors regular sets
  We extend the results of P. Shvartsman on characterizing the traces of Besov and Triebel-Lizorkin spaces on Ahlfors $n$-regular sets to the case of $d$-regular sets, $n-1<d<n$. The characterizations of trace spaces are given in terms of local polynomial approximations. 
Lizaveta Ihnatsyeva and Antti V. V\"ah\"akangas
math.FA