Fully redundant classical FETI (a) and all-floating FETI (b) formulation: Ω0,i, i = 1, … , 5, denote the local subdomains, the black dots correspond to the subdomain vertices and the dashed lines correspond to the constraints (34). The gray strip indicates Dirichlet boundary conditions. Note that the number of constraints for the all-floating approach rises with the number of vertices on the Dirichlet boundary.