“…Garcia-Castillo are with the Department of Signal Theory and Communications, University Carlos III of Madrid, 28911, Leganes, Spain (e-mail: aamor@ing.uc3m.es, legcasti@ing.uc3m.es) O. Floch, L.L. Toth, and R. Dyczij-Edlinger are with the Lehrstuhl für Theoretische Elektrotechnik, Universität des Saarlandes, Saarbrücken [18], [19], [20], [21], [22], [23], [24], [25], [26], [27], [28], [29], [30], [31], [32], [33], [34], [35], [36], [37], [38], [39], [40], [41], [42]. All these references can be divided into three groups: i) optimized Schwarz methods, focused on the optimization of the so-called transmission conditions, [16], [25], [30]; ii) cement element methods, which use transmission conditions through the definition of cement variables with physical meaning, [13], [14], [17], [18], [19], [20], [21], [22]; iii) finite element tear and interconnecting (FETI) methods, which use Lagrange multipliers to obtain a reduced system of equations, [15], [23], [26], [27], [24], [32],…”