ABSTRACT
In our theoretical analysis, we assume that the subregions, are tetrahedra
or parallelepipeds and that they are shape regular, i.e., not very thin. We also
assume that if a face of a subdomain intersects dQo, then the measure of this set is comparable to that of the face. Similarly, if an edge of a subdomain
intersects dQo, we assume that the length of this intersection is bounded from below in terms of the length of the edge as a whole. For the FETI methods and the case of arbitrary coefficients, pi, we also have to make a further assumption on the geometry of the decomposition.
