We classify conformally flat Riemannian 3−manifolds which possesses a free isometric S−action.

We prove that any compact complex surface with c1 > 0 admits an Einstein metric which is conformally related to a Kähler metric. The key new ingredient is the existence of such a metric on the blow-up CP2#2CP2 of the complex projective plane at two distinct points.

The Bμ/μ solution in GMSB via the hidden sector dynamics is simple and natural. However, it has some obstacles to be physical. To circumvent this situation, we introduce the visible and the hidden branes, each of which has its own U(1) symmetry, in a five dimensional setup. In the bulk we allow Chern-Simons coupling between the visible and the hidden U(1)s which gives an enhancement of the mass...