 Around 1970, Michel Raynaud provided an interpretation of certain rigid analytic spaces as formal models, i.e., as generic fibers of formal schemes over the valuation ring "R" of "k".In particular, he showed that the category of quasi-compact quasi-separated rigid spaces over "k" is equivalent to the localization of the category of quasi-compact admissible formal schemes over "R" with respect to admissible formal blow-ups.Here, a formal scheme is admissible if it is coverable by formal spectra of topologically finitely presented "R" algebras whose local rings are "R"-flat.