2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/186730We consider non-supersymmetric four-dimensional closed string theories constructed out of tensor products of N=2 minimal models. Generically such theories have closed string tachyons, but these may be removed either by choosing a non-trivial partition function or a suitable Klein bottle projection. We find large numbers of examples of both types.9 pages, 1 tableHigh Energy Physics - Theorytext