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In this paper we confirm a folklore conjecture which suggests that for a complete noncompact manifold $M$ of finite volume with sectional curvature $-1 \leq K \leq 0$, if the universal cover of $M$ is a visibility manifold, then the…

Geometric Topology · Mathematics 2024-05-30 Ran Ji , Yunhui Wu

A smooth five-dimensional s-cobordism becomes a smooth product if stabilized by a finite number n of $S^2xS^2x[0,1]$'s. We show that for amenable fundamental groups, the minimal n is subextensive in covers, i.e., n(cover)/index(cover) has…

Geometric Topology · Mathematics 2015-03-19 Michael Freedman , Larry Guth , Emmy Murphy

We prove a result on equivariant deformations of flat bundles, and as a corollary, we obtain two ``splitting in a finite cover'' theorems for isometric group actions on Riemannian manifolds with infinite fundamental groups, where the…

Differential Geometry · Mathematics 2007-05-23 Igor Belegradek

We prove that on closed Riemannian manifolds with infinite abelian, but not cyclic, fundamental group, any isometry that is homotopic to the identity possesses infinitely many invariant geodesics. We conjecture that the result remains true…

Differential Geometry · Mathematics 2015-05-13 Marco Mazzucchelli

We show that the canonical contact structure on the link of a normal complex singularity is universally tight. As a corollary we show the existence of closed, oriented, atoroidal 3-manifolds with infinite fundamental groups which carry…

Geometric Topology · Mathematics 2012-06-13 Yanki Lekili , Burak Ozbagci

The fundamental groups of most (conjecturally, all) closed 3-manifolds with uniform geometries have finite complete rewriting systems. The fundamental groups of a large class of amalgams of circle bundles also have finite complete rewriting…

Group Theory · Mathematics 2008-02-03 Susan Hermiller , Michael Shapiro

We give a version of Gromov's compactess theorem for pseudoholomorphic curves in the case of quasiregular mappings between closed manifolds. More precisely we show that, given $K\ge 1$ and $D\ge 1$, any sequence $(f_n \colon M \to N)$ of…

Differential Geometry · Mathematics 2019-04-02 Pekka Pankka , Juan Souto

We prove continuity results for new stability thresholds related to uniform K-stability and deduce that uniform K-stability is an open condition in the K\"ahler cone of any compact K\"ahler manifold, thus establishing an algebro-geometric…

Differential Geometry · Mathematics 2022-03-01 Zakarias Sjöström Dyrefelt

We give an example of a symplectic manifold with a stable hypersurface such that nearby hypersurfaces are typically unstable.

Symplectic Geometry · Mathematics 2009-08-19 K. Cieliebak , U. Frauenfelder , G. P. Paternain

We show that a pseudo-holomorphic embedding of an almost-complex $2n$-manifold into almost-complex $(2n + 2)$-Euclidean space exists if and only if there is a CR regular embedding of the $2n$-manifold into complex $(n + 1)$-space. We remark…

Differential Geometry · Mathematics 2018-04-24 Rafael Torres

A well-known property of unordered configuration spaces of points (in an open, connected manifold) is that their homology stabilises as the number of points increases. We generalise this result to moduli spaces of submanifolds of higher…

Algebraic Topology · Mathematics 2021-08-18 Martin Palmer

For each nonnegative integer m we show that any closed, oriented topological four-manifold with fundamental group Z_{4m+2} and odd intersection form, with possibly seven exceptions, either admits no smooth structure or admits infinitely…

Geometric Topology · Mathematics 2024-06-14 R. Inanc Baykur , Andras I. Stipsicz , Zoltan Szabo

We exhibit a closed aspherical 5-manifold of nonpositive curvature that fibers over a circle whose fundamental group is hyperbolic relative to abelian subgroups such that the fiber is a closed aspherical 4-manifold whose fundamental group…

Geometric Topology · Mathematics 2021-06-17 Koji Fujiwara

We will simplify earlier proofs of Perelman's collapsing theorem for 3-manifolds given by Shioya-Yamaguchi and Morgan-Tian. Among other things, we use Perelman's critical point theory (e.g., multiple conic singularity theory and his…

Differential Geometry · Mathematics 2010-10-12 Jianguo Cao , Jian Ge

By introducing the notion of distributive constant for a family of closed subschemes, we establish a general form of the second main theorem for algebraic nondegenerate meromorphic mappings from a generalized $p$-Parabolic manifold into a…

Complex Variables · Mathematics 2026-02-17 Si Duc Quang

It follows from the work of Kapovitch and Wilking that a closed manifold with nonnegative Ricci curvature has an almost nilpotent fundamental group. Leftover questions and conjectures have asked if in this context the fundamental group is…

Differential Geometry · Mathematics 2026-05-29 Elia Bruè , Aaron Naber , Daniele Semola

We generalize the notion of essential closures which is used in formulating a geometric necessary condition for a set to be the support of a multivariate copula. Furthermore, in some special cases, we derive an explicit formula of the…

Statistics Theory · Mathematics 2012-07-26 Pongpol Ruankong , Songkiat Sumetkijakan

A manifold $M^n$ inherits a labeled $n$-dimensional graph $\widetilde{M}[G^L]$ structure consisting of its charts. This structure enables one to characterize fundamental groups of manifolds, classify those of locally compact manifolds with…

General Mathematics · Mathematics 2010-06-21 Linfan Mao

It is an important question whether it is possible to put a geometry on a given manifold or not. It is well known that any simply connected closed manifold admitting a real projective structure must be a sphere. Therefore, any simply…

Geometric Topology · Mathematics 2018-11-26 Hatice Çoban

In this article a class of closed convex sets in the Euclidean $n$-space which are the convex hull of their profiles is described. Thus a generalization of Krein-Milman theorem\cite{Lay:1982} to a class of closed non-compact convex sets is…

Metric Geometry · Mathematics 2013-01-07 M. Beltagy , S. Shenawy