A quasi–regular Sasakian structure on a manifold L is equivalent to writing L as the unit circle subbundle of a holomorphic Seifert C-bundle over a complex algebraic orbifold (X,∆ = ∑ (1− 1 mi )Di). The Sasakian structure is called positive if the orbifold first Chern class c1(X) − ∆ = −(KX + ∆) is positive. We are especially interested in the case when the Riemannian metric part of the Sasakia...

Exact solutions of the Einstein-Maxwell equations that describe moving black holes in a cosmological setting are discussed with the aim of discovering the global structure and testing cosmic censorship. Continuation beyond the horizons present in these solutions is necessary in order to identify the global structure. Therefore the possibilities and methods of analytic extension of geometries ar...

We investigate which three dimensional near-horizon metrics gNH admit a compatible 1-form X such that (X, [gNH ]) defines an Einstein-Weyl structure. We find explicit examples and see that some of the solutions give rise to Einstein-Weyl structures of dispersionless KP type and dispersionless Hirota (aka hyperCR) type.

The general structure of the scalar cosets of the Maxwell-Einstein supergravities is given. Following an introduction of the non-linear coset formalism of the supergravity theories a comparison of the coset algebras of the Maxwell-Einstein supergravities in various dimensions is discussed.

In this article, we consider the almost Hermitian structure on TM induced by a pair of a metric and an affine connection on M . We find the conditions under which TM admits almost Kähler structures, Kähler structures and Einstein metrics, respectively. Moreover, we give two examples of Kähler-Einstein structures on TM . 2000 Mathematics Subject Classification: 53C55, 53C15, 53C25.

We consider 6-dimensional nearly Kähler manifolds M and prove that any totally geodesic hypersurface N of M is a Sasaki-Einstein manifold, and so it has a hypo structure in the sense of [8]. We show that such a hypo structure defines a nearly Kähler structure on N × R, and a compact nearly Kähler structure with conical singularities on N 5 × S 1 when N is compact. Moreover, an extension of the ...

the asymptotically ads solutions of the einstein gravity with hyperbolic horizons in the presence of so(n(n-1)/2- 1,1) yang-mills fields governed by the non-abelian born-infeld lagrangian are presented. we investigate the properties of these solutions as well as their asymptotic behavior in various dimensions. the properties of these kinds of solutions are like the einstein-yang-mills solutions...