Let Ω⊂$R$^{$n$}be an arbitrary open set. In this paper it is shown that if a Sobolev function$f$∈$W$^{1,$p$}(Ω) possesses a zero trace (in the sense of Lebesgue points) on ϖΩ, then$f$is weakly zero on ϖΩ in the sense that$f$∈$W$_{0}^{1,$p$}(Ω).
Nikolai NikolovInstitute of Mathematics and Informatics, Bulgarian Academy of SciencesPeter PflugFakultät V Institut für Mathematik, Carl von Ossietzky Universität Oldenburg