arXiv research

Analytic sets with unique infinite tangent cone are algebraic.

Study of tangent cones at infinity for algebraic sets.

New Calabi-Yau metrics found on complex symmetric spaces.

It is shown by Colding and Minicozzi the uniqueness of the tangent cone at infinity of Ricci-flat manifolds with Euclidean volume growth which has at least one tangent cone at infinity with a smooth cross section. In this article we raise an example of the Ricci-flat manifold implying that the assumption for the volume…

Uniqueness proven for stable hypersurface tangent cones.

Study shows finitely generated fundamental groups for certain nonnegative Ricci curvature manifolds.

Identifies scales in Ricci-flat manifolds at infinity.

We show that for any Ricci-flat manifold with Euclidean volume growth the tangent cone at infinity is unique if one tangent cone has a smooth cross-section. Similarly, for any noncollapsing limit of Einstein manifolds with uniformly bounded Einstein constants, we show that local tangent cones are unique if one tangent …

New example of non-Kähler soliton with Kähler-like behavior at infinity.

A lower-bound estimate of injectivity radius for complete Riemannian manifolds is discussed in a pure geometric viewpoint and is applied to study tangent cones at infinity of certain gradient Ricci solitons. We also study the asymptotic volume ratio of gradient Ricci solitons.

New Calabi-Yau metrics constructed with detailed geometry at infinity.

New methods compute geometry of hyperKähler metrics at infinity.

Unique Calabi-Yau metrics found on C^n.

Study fundamental groups of manifolds with nonnegative Ricci curvature and stability at infinity.

Study ancient Ricci flows with nonnegative Ricci curvature and their asymptotic geometry.

We construct infinitely many complete Calabi-Yau metrics on $\mathbf{C}^n$ for $n \geq 3$, with maximal volume growth, and singular tangent cones at infinity. In addition we construct Calabi-Yau metrics in neighborhoods of certain isolated singularities whose tangent cones have singular cross section, generalizing work…

Study inverse mean curvature flow on non-compact hypersurfaces, proving long-term existence and characterizing maximal time.

We partially resolve a conjecture of Meeks on the asymptotic behavior of minimal surfaces in $\mathbb{R}^3$ with quadratic area growth.

The paper shows that certain manifolds with nonnegative Ricci curvature have finitely generated fundamental groups.

Study on higher-dimensional quasigeodesics in metric spaces.

Constructs complete Calabi-Yau metrics from smoothed Calabi-Yau intersections.

Let (M,d) be a metric space. For 0<r<R, and p in M let G(p,r,R) be the group obtained by considering all loops based at p whose image is contained in the closed ball of radius r and identifying two loops if there is a homotopy betweeen them that is contained in the open ball of radius R. In this paper we study the asym…

The paper studies minimal graphs with bounded 2-dilation in Euclidean space.

The study proves unique and isolated properties of Einstein 5-manifolds via gap theorems in 4 dimensions.

The study proves properties of capillary graphs in half-spaces.

We proved a uniqueness theorem of tangent connections for a Yang-Mills connection with an isolated singularity with a quadratic growth of the curvature at the singularity. We also obtained controls over the rate of the asymptotic convergence of the connection to the tangent connection under assumptions that the connect…

For each $n\ge 3$, we construct on $\mathbb{C}^n$ examples of complete Calabi-Yau metrics of Euclidean volume growth having a tangent cone at infinity with singular cross-section.

Study harmonic functions on submanifolds and their cones.

The study bounds harmonic functions on manifolds with nonnegative Ricci curvature.

In this paper, we study self-expanding solutions for mean curvature flows and their relationship to minimal cones in Euclidean space. In [18], Ilmanen proved the existence of self-expanding hypersurfaces with prescribed tangent cones at infinity. If the cone is $C^{3,α}$-regular and mean convex (but not area-minimizing…

We mainly study 3-dimensional complete gradient Ricci solitons with positive sectional curvature, whose scalar curvature attains its maximum at some point. In section 2, we estimate the area growth of level sets and the volume growth of sublevel sets of a Ricci potential. In section 3, we show that the scalar curvature…

Given a smooth, symmetric, homogeneous of degree one function $f=f\left(λ_{1},\cdots,\,λ_{n}\right)$ satisfying $\partial_{i}f>0$ for all $i=1,\cdots,\, n$, and an oriented, properly embedded smooth cone $\mathcal{C}^n$ in $\mathbb{R}^{n+1}$, we show that under some suitable conditions on $f$ and the covariant derivati…

New metrics on C^3 defy uniqueness, differing even at infinity.

We study the asymptotic volume ratio of non-steady gradient Ricci solitons. Moreover, a local estimate of the volume ratio is obtained for expanding solitons which satisfy $\lim_{dist(O,x)\rightarrow\infty} |Sect|\cdot dist(O,x)^2=0$. Therefore, for such a soliton, we can show that it must have $\mathbb{R}^n$ as one of…

We construct a metric simplicial complex which is an almost isometric model of the moduli space M(S) of Riemann surfaces. We then use this model to compute the "tangent cone at infinity" of M(S): it is the topological cone on the quotient of the complex of curves C(S) by the mapping class group of S, endowed with an ex…

This is the first part in a two-part series on complete Calabi-Yau manifolds asymptotic to Riemannian cones at infinity. We begin by proving general existence and uniqueness results. The uniqueness part relaxes the decay condition $O(r^{-n-ε})$ needed in earlier work to $O(r^{-ε})$, relying on some new ideas about harm…

We prove compactification theorems for some complete Kähler manifolds with nonnegative Ricci curvature. Among other things, we prove that a complete noncompact Kähler Ricci flat manifold with maximal volume growth and quadratic curvature decay is a crepant resolution of a normal affine algebraic variety. Furthermore, s…

New Einstein RCD spaces found with cone singularities.

Motivated by the study of collapsing Calabi-Yau threefolds with a Lefschetz K3 fibration, we construct a complete Calabi-Yau metric on $\mathbb{C}^3$ with maximal volume growth, which in the appropriate scale is expected to model the collapsing metric near the nodal point. This new Calabi-Yau metric has singular tangen…

Study shows unique tangent cones for area-minimizing currents at boundary points.

Uniqueness proven for cylindrical tangent cones in high dimensions.

New examples of Calabi-Yau metrics on cones with irregular smooth links.

Let X be a compact Kahler orbifold without \C-codimension-1 singularities. Let D be a suborbifold divisor in X such that D \supset Sing(X) and -pK_X = q[D] for some p, q \in \N with q > p. Assume that D is Fano. We prove the following two main results. (1) If D is Kahler-Einstein, then, applying results from our previo…

Unique tangent cones found for boundary points of 2D almost-minimizing currents.

Minimal hypersurfaces with cylindrical tangent cones constructed and analyzed.

Study minimal graphs on non-negative Ricci curvature manifolds.

Paper solves Dirichlet problem at infinity for Riemannian cones.

We proved two Three Circles Theorems for harmonic functions on manifolds in integral sense. As one application, on manifold with nonnegative Ricci curvature, whose tangent cone at infinity is the unique metric cone with unique conic measure, we showed the existence of nonconstant harmonic functions with polynomial grow…