Gromov-Hausdorff limits of K\"ahler manifolds with bisectional curvature lower bound I

Given a sequence of complete(compact or noncompact) K\"ahler manifolds $M^n_i$ with bisectional curvature lower bound and noncollapsed volume, we prove that the pointed Gromov-Hausdorff limit is homeomorphic to a normal complex analytic space. The complex analytic structure is the natural "limit" of complex structure of $M_i$.Comment: 26 page

Compactification of certain K\"ahler manifolds with nonnegative Ricci curvature

We prove compactification theorems for some complete K\"ahler manifolds with nonnegative Ricci curvature. Among other things, we prove that a complete noncompact K\"ahler Ricci flat manifold with maximal volume growth and quadratic curvature decay is a crepant resolution of a normal affine algebraic variety. Furthermore, such affine variety degenerates in two steps to the unique metric tangent cone at infinity.Comment: 20 page

On Yau's uniformization conjecture

Let $M^n$ be a complete noncompact K\"ahler manifold with nonnegative bisectional curvature and maximal volume growth, we prove that $M$ is biholomorphic to $\mathbb{C}^n$. This confirms Yau's uniformization conjecture when M has maximal volume growth.Comment: Improvement of earlier versio

Gromov-Hausdorff limit of K\"ahler manifolds and the finite generation conjecture

We study the uniformization conjecture of Yau by using the Gromov-Haudorff convergence. As a consequence, we confirm Yau's finite generation conjecture. More precisely, on a complete noncompact K\"ahler manifold with nonnegative bisectional curvature, the ring of polynomial growth holomorphic functions is finitely generated. During the course of the proof, we prove if $M^n$ is a complete noncompact K\"ahler manifold with nonnegative bisectional curvature and maximal volume growth, then $M$ is biholomorphic to an affine algebraic variety. We also confirm a conjecture of Ni on the existence of polynomial growth holomorphic functions on K\"ahler manifolds with nonnegative bisectional curvature.Comment: some typos correcte

Extended Dynamical Equations of the Period Vectors of Crystals under Constant External Stress to Many-body Interactions

Since crystals are made of periodic structures in space, predicting their three period vectors starting from any values based on the inside interactions is a basic theoretical physics problem. For the general situation where crystals are under constant external stress, we derived dynamical equations of the period vectors in the framework of Newtonian dynamics, for pair potentials recently (doi:/10.1139/cjp-2014-0518). The derived dynamical equations show that the period vectors are driven by the imbalance between the internal and external stresses. This presents a physical process where when the external stress changes, the crystal structure changes accordingly, since the original internal stress can not balance the external stress. The internal stress has both a full kinetic energy term and a full interaction term. It is extended to many-body interactions in this paper. As a result, all conclusions in the pair-potential case also apply for many-body potentials.Comment: 15 pages, 2 figure. arXiv admin note: text overlap with arXiv:cond-mat/020937

On the tangent cone of K\"ahler manifolds with Ricci curvature lower bound

Let $X$ be the Gromov-Hausdorff limit of a sequence of pointed complete K\"ahler manifolds $(M^n_i, p_i)$ satisfying $Ric(M_i)\geq -(n-1)$ and the volume is noncollapsed. We prove that, there exists a Lie group isomorphic to $\mathbb{R}$, acting isometrically, on the tangent cone at each point of $X$. Moreover, the action is locally free on the cross section. This generalizes the metric cone theorem of Cheeger-Colding to the K\"ahler case. We also discuss some applications to complete K\"ahler manifolds with nonnegative bisectional curvature.Comment: 16page

Local volume comparison for Kahler manifolds

On Kahler manifolds with Ricci curvature lower bound, assuming the real analyticity of the metric, we establish a sharp relative volume comparison theorem for small balls. The model spaces being compared to are complex space forms, i.e, Kahler manifolds with constant holomorphic sectional curvature. Moreover, we give an example showing that on Kahler manifolds, the pointwise Laplacian comparison theorem does not hold when the Ricci curvature is bounded from below.Comment: 15 page

3-manifolds with nonnegative Ricci curvature

For a noncompact 3-manifold with nonnegative Ricci curvature, we prove that either it is diffeomorphic to $\mathbb{R}^3$ or the universal cover splits. As a corollary, it confirms a conjecture of Milnor in dimension 3.Comment: Revised version, accepted by Inventiones Mathematica

Comment on "Crystal Structure and Pair Potentials: A Molecular-Dynamics Study"

The dynamical equations for particles in the Parrinello-Rahman Molecular Dynamics were compared with the Newton's Second Law. The discrepancy is due to using the in-complete particles' kinetic energy in the Lagrangian.Comment: 1 page, no figur

Higher-degree Smoothness of Perturbations I

This paper was originated from overcoming the analytic difficulty in our method for constructing virtual moduli cycles in Gromov-Witten/Floer theory using global perturbations. We will discuss a new point of view on the analytic difficulty caused by the lack of smoothness of the action of the reparametrization group $G$ on the spaces of Sobolev maps. We show that how this negative aspect of the lack of smoothness of $G$-action can be made into a positive and crucial analytic input stated in Theorem 1.1, from which all analytic results used in GW/Floer theory related to the lack of smoothness can be treated in a uniform and simple manner.Comment: 22 page