2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/53269A construction of elements of the BRS cohomology of ghost number +/- 1 in c<1 string theory is described, and their two-point function computed on the sphere. The construction makes precise the relation between these extra states and null vectors. The physical states of ghost number +1 are found to be exact forms with respect to a ``conjugate'' BRS operator.11 Pages (Talk given at Cargese Summer School, July 1991)High Energy Physics - Theorytext