We consider type II string theory in space-time backgrounds which admit eight supercharges. Such backgrounds are characterized by the existence of a (generically nonintegrable) generalized SU (3)Ã—SUâ€¦ (More)

This paper analyses type II string theories in backgrounds which admit an SU (3)Ã—SU (3) structure. Such backgrounds are designed to linearly realize eight out of the original 32 supercharges and as aâ€¦ (More)

We derive the fiveâ€“dimensional effective action of strongly coupled heterotic string theory for the complete (1, 1) sector of the theory by performing a reduction, on a Calabiâ€“Yau threeâ€“fold, ofâ€¦ (More)

We systematically analyse the necessary and sufficient conditions for the preservation of supersymmetry for bosonic geometries of the form R1,9âˆ’d Ã— Md, in the common NS-NS sector of type II stringâ€¦ (More)

We present a countably infinite number of new explicit co-homogeneity one Sasakiâ€“Einstein metrics on S Ã— S, in both the quasi-regular and irregular classes. These give rise to new solutions of typeâ€¦ (More)

We analyse the most general supersymmetric solutions of D = 11 supergravity consisting of a warped product of five-dimensional anti-de-Sitter space with a six-dimensional Riemannian space M6, withâ€¦ (More)

The low-energy D = 4, N = 1 effective action of the strongly coupled heterotic string is explicitly computed by compactifying HoÅ™ava-Witten theory on the deformed Calabi-Yau threefold solution due toâ€¦ (More)

We construct D = 10 supergravity solutions corresponding to type IIB fivebranes wrapping a two-sphere in a Calabiâ€“Yau two-fold. These are related in the IR to the large N limit of pure N = 2 SU(N)â€¦ (More)

We construct vacua of Mâ€“theory on S1/Z2 associated with Calabiâ€“Yau three-folds. These vacua are appropriate for compactification to N = 1 supersymmetry theories in both four and five dimensions. Weâ€¦ (More)

We show that for every positive curvature KÃ¤hlerâ€“Einstein manifold in dimension 2n there is a countably infinite class of associated Sasakiâ€“ Einstein manifolds X2n+3 in dimension 2n + 3. When n = 1â€¦ (More)