Joaquim BrunaDepartment de Matemàtiques, Universitat Autònoma de BarcelonaJoaquin M. OrtegaDepartment de Matemàtiques, Universitat Autònoma de Barcelona
We study removable sets for the Sobolev space$W$^{1,p}. We show that removability for sets lying in a hyperplane is essentially determined by their thickness measured in terms of a concept of$p$-porosity.