摘要: We choose the rules of wormhole calculus, used by Coleman in the context of Euclidean quantum gravity to show that the cosmological constant vanishes,to the simple case of a scalar field theory, the λφ~4 model. we calculate one and two point functions in one subuniverse approximation. Wormholes make first order transition disappear, but permit second order transition. We discuss another way to deal with the divergences caused by arbitrarily large numbers of subuniverse.