Huiszoon, LennaertSchellekens, AdrianusSousa, Nuno2013-01-242013-01-241999Huiszoon, Lennaert; Schellekens, Adrianus; Sousa, Nuno - Klein bottles and simple currents. "Physics Letters B" [Em linha]. ISSN 0370-2693. Vol. 470 (Dez. 1999), p. 95-1020370-2693http://hdl.handle.net/10400.2/2342The standard Klein bottle coefficient in the construction of open descendants is shown to equal the Frobenius-Schur indicator of a conformal field theory. Other consistent Klein bottle projections are shown to correspond to simple currents. These observations enable us to generalize the standard open string construction from C-diagonal parent theories to include non-standard Klein bottles. Using (generalizations of) the Frobenius-Schur indicator we prove positivity and integrality of the resulting open and closed string state multiplicities for standard as well as non-standard Klein bottles.engFísicaTeoria de cordasPhysicsString theoryjournal article