“…We are interested here in designing and analyzing domain decomposition methods for complex diffusion problems of the form (1.1) that use optimized transmission conditions; for an analysis of the performance of the classical Schwarz method, see [12]. Traditionally, such transmission conditions are derived and optimized for simple two subdomain configurations, like in optimized Schwarz methods, see [6,17,3,19,11,21,20,22,1,16,15] and references therein. We investigate here the optimization of transmission conditions directly for the many subdomain case, and also study the optimization problem in the limit when the number of subdomains goes to infinity, using the tool of limiting spectra, see [2] and the references therein.…”