arXiv research

Study on RCD(0,N) spaces with small linear diameter growth.

Random surfaces' diameter grows logarithmically with size.

In this paper we study the Weil-Petersson geometry of $\overline{\mathcal{M}_{g,n}}$, the compactified moduli space of Riemann surfaces with genus g and n marked points. The main goal of this paper is to understand the growth of the diameter of $\overline{\mathcal{M}_{g,n}}$ as a function of $g$ and $n$. We show that t…

Study shows convergence of immortal Ricci flows under certain conditions.

We prove a Liouville property for any $f$-harmonic function with polynomial growth on a complete noncompact smooth metric measure space $(M,g,e^{-f}dv)$ when the Bakry-Émery Ricci curvature is nonnegative and its diameter of geodesic sphere has sublinear growth.

Minimal hyperbolic surface diameter grows logarithmically with genus.

In 1968, Milnor conjectured that a complete noncompact manifold with nonnegative Ricci curvature has a finitely generated fundamental group. The author applies the Excess Theorem of Abresch and Gromoll (1990), to prove two theorems. The first states that if such a manifold has small linear diameter growth then its fund…

We survey all results concerning the topology of complete noncompact Riemannian manifolds with nonnegative Ricci curvature that have no additional conditions other than restrictions to the dimension, volume growth or diameter growth of the manifold. We will also present relevant examples and list open problems.

We prove that the cardinality of the torsion subgroups in homology of a closed hyperbolic manifold of any dimension can be bounded by a doubly exponential function of its diameter. It would follow from a conjecture by Bergeron and Venkatesh that the order of growth in our bound is sharp. We also determine how the numbe…

Maximal distortion between geodesic and Euclidean diameters in polygonal domains is studied.

Study on positive scalar curvature and its impact on Ricci limit spaces.

Since non-compact RCD(0, N) spaces have at least linear volume growth, we study noncompact RCD(0, N) spaces with linear volume growth in this paper. One of the main results is that the diameter of level sets of a Busemann function grow at most linearly on a noncompact RCD(0, N) space satisfying the linear volume growth…

Study surfaces with nonnegative curvature in spectral sense, proving inequalities and bounds.

The main results of this paper consists of two parts. Firstly, we obtain an almost rigidity theorem which says that on a RCD(0, N) space, when a domain between two level sets of a distance function has almost maximal volume compared to that of a cylinder, then this portion is close to a cylinder as a metric space. Seco…

Study of manifolds with nonnegative Ricci curvature and slow relative volume growth.

We study the growth of harmonic functions on complete Riemann-ian manifolds where the extrinsic diameter of geodesic spheres is sublinear. It is an generalization of a result of A. Kazue. We also get a Cheng and Yau estimates for the gradient of harmonic functions.

Uniform models for random 3-manifolds with controlled metrics.

We consider complete noncompact Riemannian manifolds with quadratically decaying lower Ricci curvature bounds and minimal volume growth. We first prove a rigidity result showing that ends with strongly minimal volume growth are isometric to warped product manifolds. Next we consider the almost rigid case in which manif…

The study proves manifolds with specific curvature and volume properties always split off a line at infinity.

Book introduces Hofer's metric on symplectic diffeomorphisms.

Study volume growth and asymptotic cones of nonnegative Ricci curvature manifolds.

Paper reduces sample complexity for bilinear systems identification to nearly constant.

This paper is about the geometry of flip-graphs associated to triangulations of surfaces. More precisely, we consider a topological surface with a privileged boundary curve and study the spaces of its triangulations with n vertices on the boundary curve. The surfaces we consider topologically fill this boundary curve s…

Deep learning predicts plant growth and yield in greenhouses.

Graphs on surfaces have a 2-dimensional large scale structure.

We prove mean curvature and volume comparison estimates on smooth metric measure spaces when their integral Bakry-Émery Ricci tensor bounds, extending Wei-Wylie's comparison results to the integral case. We also apply comparison results to get diameter estimates, eigenvalue estimates and volume growth estimates on smoo…

We study solutions of the mean curvature flow which are defined for all negative curvature times, usually called ancient solutions. We give various conditions ensuring that a closed convex ancient solution is a shrinking sphere. Examples of such conditions are: a uniform pinching condition on the curvatures, a suitable…

The Milnor Problem (modified) in the theory of group growth asks whether any finite presented group of vanishing algebraic entropy has at most polynomial growth. We show that a positive answer to the Milnor Problem (modified) is equivalent to the Nilpotency Conjecture in Riemannian geometry: given $n, d>0$, there exist…

IPMs struggle with hyperbolic spaces due to polynomially growing barrier parameters.

Torus covers have controlled volume and diameter under curvature and diameter bounds.

Short proof shows infinite diameter for surface diffeomorphisms.

The study shows how many diameter directions in Besse manifolds relate to Blaschke manifolds.

For certain manifolds, nonnegative Ricci curvature limits dimension and forces almost abelian fundamental group.

Diameters of ball intersections decrease as centers move apart.

Exact diameter found for some Riemann surfaces.

The paper proves that Kähler manifolds with positive holomorphic sectional curvature have a limited diameter.

Sharp diameter bounds for Calabi-Yau degenerations proved.

Sharp bound on smallest diameter of hyperbolic surfaces.

Maximal diameter theorem for graphs with positive Ricci curvature.

Study on compact Quasi-Einstein manifolds yields diameter estimates and Hitchin-Thorpe inequality conditions.

Spheres can be stretched to have larger diameter than antipodal distance.

Max diameter Kahler manifolds with positive bisectional curvature are complex projective spaces.

Makeev proved that among centrally symmetric four-dimensional polytopes, with more than twenty facets and circumscribed about the Euclidean ball of diameter one, there is no universal cover for the family of unit diameter sets. In this paper we examine the converse problem, and prove that each centrally symmetric polyt…

Small sub-Riemannian balls have diameter close to twice their radius.

Extends diameter bounds for submanifolds with boundary and minor curvature restrictions.

Develop an ABP approach to Sobolev and Michael-Simon inequalities beyond Euclidean volume growth.

Uniform estimates for Kaehler metrics' diameters and volumes.

Quotient spaces of high-dimensional spheres have either zero or large diameter.