We continue our study of matrix models of dually weighted graphs. Among the attractive features of these models is the possibility to interpolate between ensembles of regular and random two-dimensional lattices, relevant for the study of the crossover from twodimensional flat space to two-dimensional quantum gravity. We further develop the formalism of large N character expansions. In particula...

We establish structure theorems for a smooth projective variety $X$ with semi-positive holomorphic sectional curvature. first prove that is rationally connected if has no truly flat tangent vectors at some point (which satisfied when the curvature quasi-positive). This result solves Yau's conjecture on positive in strong form. Moreover, we admits locally trivial morphism $\phi:X\to Y$ such fibe...

This paper relates the boundary term in the Chern-Gauss-Bonnet formula on 4-manifolds M with the renormalized volume V , as defined in the AdS/CFT correspondence, for asymptotically hyperbolic Einstein metrics on M . In addition we compute and discuss the differential or variation dV of V , or equivalently the variation of the L norm of the Weyl curvature, on the space of such Einstein metrics....

We calculate the metric on the D-brane vacuum moduli space for backgrounds of the form C 3 /Γ for cyclic groups Γ. In the simplest procedure — starting with a flat " seed " metric on the covering space — we find that the resulting D-brane metric is not Ricci-flat. We argue that this is likely to be true of the true 0-brane metric at weak string coupling.

Let (M, ∂M) be a compact 3-manifold with boundary which admits a complete, convex co-compact hyperbolic metric. We are interested in the following question: Question A Let h be a (non-smooth) metric on ∂M , with curvature K > −1. Is there a unique hyperbolic metric g on M , with convex boundary, such that the induced metric on ∂M is h ? There is also a dual statement: Question B Let h be a (non...

Abstract: Motivated by problems related to quasi-local mass in general relativity, we study the static metric extension conjecture proposed by R. Bartnik [4]. We show that, for any metric on B̄1 that is close enough to the Euclidean metric and has reflection invariant boundary data, there always exists an asymptotically flat and scalar flat static metric extension in M = R \B1 such that it satis...

We show that there exist non-trivial piecewise-linear (PL) knots with isolated singularities Sn−2 ⊂ Sn, n ≥ 5, whose complements have the homotopy type of a circle. This is in contrast to the case of smooth, PL locally-flat, and topological locally-flat knots, for which it is known that if the complement has the homotopy type of a circle, then the knot is trivial. It is well-known that if the c...

Divergence functions are the non-symmetric “distance” on the manifold,Mθ, of parametric probability density functions over a measure space, (X,μ). Classical information geometry prescribes, on Mθ: (i) a Riemannian metric given by the Fisher information; (ii) a pair of dual connections (giving rise to the family of α-connections) that preserve the metric under parallel transport by their joint a...