We perform a generalised Scherk-Schwarz reduction of the effective action of the het-erotic string on T 6 to obtain a massive N = 4 supergravity theory in four dimensions. The local symmetry-group of the resulting d = 4 theory includes a Heisenberg group, which is a subgroup of the global O(6, 6 + n) obtained in the standard reduction. We show explicitly that the same theory can be obtained by ...

For some years there has been uncertainty over whether regularisation by dimensional reduction (DRED) is viable for non-supersymmetric theories. We resolve this issue by showing that DRED is entirely equivalent to standard dimensional regularisation (DREG), to all orders in perturbation theory and for a general renormalisable theory. The two regularisation schemes are related by an analytic red...

Three dimensional Euclidean gravity in the dreibein-spin connection formalism is investigated. We use the monopole-instanton ansatz for the dreibein and the spin connection. We show that there is a solution for the equations of motion which has a degenerate metric in three dimensions. This solution corresponds to gravity on S. PACS: 04.20.-q , 04.60.-m