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In a complete Riemannian manifold $(M, g)$ if the hessian of a real valued function satisfies some suitable conditions then it restricts the geometry of $(M, g)$. In this paper we characterize all compact rank-1 symmetric spaces, as those…

dg-ga · Mathematics 2008-02-03 Akhil Ranjan , G. Santhanam

We prove a compactness theorem for embedded measured hyperbolic Riemann surface laminations in a compact almost complex manifold $(X, J)$. To prove compactness result, we show that there is a suitable topology on the space of measured…

Geometric Topology · Mathematics 2018-01-04 Divakaran Divakaran , Dheeraj Kulkarni

In this paper we study the geodesic flow on nilmanifolds equipped with a left-invariant metric. We write the underlying definitions and find general formulas for the Poisson involution. As an example we develop the Heisenberg Lie group…

Differential Geometry · Mathematics 2019-07-24 Alejandro Kocsard , Gabriela P. Ovando , Silvio Reggiani

An equivariant Thom isomorphism theorem in operator K-theory is formulated and proven for infinite rank Euclidean vector bundles over finite dimensional Riemannian manifolds. The main ingredient in the argument is the construction of a…

K-Theory and Homology · Mathematics 2007-05-23 Jody Trout

We extend the Polydisk Theorem for symmetric bounded domains to Cartan-Hartogs domains, and apply it to prove that a Cartan-Hartogs domain inherits totally geodesic submanifolds from the bounded symmetric domain which is based on, and to…

Differential Geometry · Mathematics 2022-07-26 Roberto Mossa , Michela Zedda

A positive mass theorem for General Relativity Theory is proved. The proof is 4-dimensional in nature, and relies completely on arguments pertaining to causal structure, the basic idea being that positive energy-density focuses null…

General Relativity and Quantum Cosmology · Physics 2008-02-03 R. Penrose , R. D. Sorkin , E. Woolgar

We find a canonical decomposition of a geodesic current on a surface of finite type arising from a topological decomposition of the surface along special geodesics. We show that each component either is associated to a measured lamination…

Geometric Topology · Mathematics 2017-10-20 Marc Burger , Alessandra Iozzi , Anne Parreau , Maria Beatrice Pozzetti

In this paper we show that every homeomorphism of the plane with the topological shadowing property has a fixed point. Also, we show that a linear isomorphism of an Euclidean space has the topological shadowing property if and only if the…

Dynamical Systems · Mathematics 2019-04-26 Gonzalo Cousillas

Recently we generalized Toponogov's comparison theorem to a complete Riemannian manifold with smooth convex boundary, where a geodesic triangle was replaced by an open (geodesic) triangle standing on the boundary of the manifold, and a…

Differential Geometry · Mathematics 2013-12-10 Kei Kondo , Minoru Tanaka

A Bott manifold is a smooth projective toric variety having an iterated $\mathbb{C} P^1$-bundle structure. A certain family of Bott manifolds is used to understand the structure of Bott--Samelson varieties (or…

Algebraic Geometry · Mathematics 2025-11-13 Junho Jeong , Jang Soo Kim , Eunjeong Lee

Let Q be a Riemannian manifold such that the Betti numbers of its free loop space with respect to some coefficient field are unbounded. We show that every contact form on its unit contangent bundle supporting the natural contact structure…

Symplectic Geometry · Mathematics 2012-06-20 Mark McLean

A classical theorem of Frankel for compact K\"ahler manifolds states that a K\"ahler S^1-action is Hamiltonian if and only if it has fixed points. We prove a metatheorem which says that when Hodge theory holds on non-compact manifolds, then…

Symplectic Geometry · Mathematics 2015-06-18 Rafe Mazzeo , Álvaro Pelayo , Tudor Ratiu

If X is a proper CAT(-1)-space and $\Gamma$ a non-elementary discrete group of isometries acting properly discontinuously on X, it is shown that the geodesic flow on the quotient space Y=X/$\Gamma$ is topologically mixing, provided that the…

Geometric Topology · Mathematics 2018-11-28 Ch. Charitos , G. Tsapogas

We prove that if two conformal embeddings between Riemann surfaces with finite topology are homotopic, then they are isotopic through conformal embeddings. Furthermore, we show that the space of all conformal embeddings in a given homotopy…

Complex Variables · Mathematics 2019-10-16 Maxime Fortier Bourque

We establish a cosymplectic counterpart of Banyaga's theorem by proving that the group of weakly Hamiltonian diffeomorphisms, $\Ham_{\eta,\omega}(M)$, is simple on any closed cosymplectic manifold. A key structural result, derived from Lie…

Symplectic Geometry · Mathematics 2025-11-11 S. Tchuiaga , P. Bikorimana

In this note we prove a nonexistence result for proper biharmonic maps from complete non-compact Riemannian manifolds of dimension \(m=\dim M\geq 3\) with infinite volume that admit an Euclidean type Sobolev inequality into general…

Differential Geometry · Mathematics 2018-07-16 Volker Branding , Yong Luo

A point is called generic for a flow preserving an infinite ergodic invariant Radon measure, if its orbit satisfies the conclusion of the ratio ergodic theorem for every pair of continuous functions with compact support and non-zero…

Dynamical Systems · Mathematics 2008-12-18 Omri Sarig , Barbara Schapira

We prove positive mass theorems for asymptotically hyperbolic and asymptotically locally hyperbolic Riemannian manifolds with black-hole-type boundaries.

General Relativity and Quantum Cosmology · Physics 2021-12-08 Piotr T. Chruściel , Gregory J. Galloway

We show that a if a Riemannian manifold admits a universal cover with bounded geometry and if 0 does not belong to the spectrum or is an isolated point in the spectrum of the Laplacian on $\ell$-forms, then there exists $1<p<2$ such that…

Spectral Theory · Mathematics 2010-06-04 Noël Lohoué

We prove a $C^\infty$ closing lemma for Hamiltonian diffeomorphisms of closed surfaces. This is a consequence of a $C^\infty$ closing lemma for Reeb flows on closed contact three-manifolds, which was recently proved as an application of…

Symplectic Geometry · Mathematics 2016-09-15 Masayuki Asaoka , Kei Irie