An unexpected topological censor

Abstract

Morris-Thorne wormholes with a cosmological constant \Lambda have been studied extensively, even allowing \Lambda to be replaced by a space variable scalar. These wormholes cannot exist, however, if \Lambda is both space and time dependent. Such a \Lambda will therefore act as a topological censor. While not likely to have a bearing on the present, possible cosmological consequences of inflation cannot be discounted.