“…Over the last decade, the range of symmetric positive definite problems for which two-level domain decomposition preconditioners can be made scalable and robust by a good choice of the coarse space has become very large by the development of so-called spectral coarse spaces. The following list gives an overview of some of these contributions: [29,30,13,15,16,14,39,40,17,1,21] for Additive Schwarz, [46] for Additive Average Schwarz, [41,1] for BDD and FETI, [26,24,10,23,11,32,25,47] for BDDC and/or FETI-DP, [20] for Optimized Schwarz and [28] in the context of boundary element methods.…”