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We prove a theorem that gives a sufficient condition for the full basic automorphism group of a complete Cartan foliation to admit a unique (finite-dimensional) Lie group structure in the category of Cartan foliations. Emphasize that the…

Differential Geometry · Mathematics 2015-06-01 N. I. Zhukova , K. I. Sheina

Given a complex Hilbert space H, we study the differential geometry of the manifold M of all projections in V:=L(H). Using the algebraic structure of V, a torsionfree affine connection $\nabla$ (that is invariant under the group of…

Functional Analysis · Mathematics 2007-05-23 J. M. Isidro , M. Mackey

Let $\Delta$ be a spherical building each of whose irreducible components is infinite, has rank at least 2 and satisfies the Moufang condition. We show that $\Delta$ can be given the structure of a topological building that is compact and…

Group Theory · Mathematics 2011-08-09 Theo Grundhofer , Linus Kramer , Hendrik Van Maldeghem , Richard M. Weiss

This paper presents a simplified geometric proof of the Molino-Alexandrino-Radeschi (MAR) Theorem, which states that the closure of a singular Riemannian foliation on a complete Riemannian manifold is itself a smooth singular Riemannian…

Differential Geometry · Mathematics 2026-05-11 Mateus de Melo , Ivan Struchiner

This is a survey paper dealing with holomorphic G-structures and holomorphic Cartan geometries on compact complex manifolds. Our emphasis is on the foliated case: holomorphic foliations with transverse (branched or generalized) holomorphic…

Differential Geometry · Mathematics 2021-07-05 Indranil Biswas , Sorin Dumitrescu

The question whether a Riemannian manifold is geodesically connected can be studied from geometrical as well as variational methods, and accurate results can be obtained by using the associated distance and related properties of the…

Differential Geometry · Mathematics 2023-04-21 Miguel Sanchez

Let (M, F) be a compact codimension-one foliated manifold whose leaves are equipped with Riemannian metrics, and consider continuous functions on M that are harmonic along the leaves of F . If every such function is constant on leaves we…

Dynamical Systems · Mathematics 2007-12-14 Sergio Fenley , Renato Feres , Kamlesh Parwani

We study conditions for the integrability of the distribution defined on a regular Poisson manifold as the orthogonal complement (with respect to some (pseudo)-Riemannian metric) to the tangent spaces of the leaves of a symplectic…

Symplectic Geometry · Mathematics 2007-05-23 Dan Fish , Serge Preston

A singular riemannian foliation on a complete riemannian manifold is said to be riemannian if each geodesic that is perpendicular at one point to a leaf remains perpendicular to every leaf it meets. The singular foliation is said to admit…

Differential Geometry · Mathematics 2007-05-23 Marcos M. Alexandrino , Dirk Toeben

Given a positive singular hermitian metric of a pseudoeffective line bundle on a complex Kaehler manifold, a singular foliation is constructed satisfying certain analytic analogues of numerical conditions. This foliation refines Tsuji's…

Algebraic Geometry · Mathematics 2007-05-23 Thomas Eckl

We study the mechanisms of the non properness of the action of the group of diffeomorphisms on the space of Lorentzian metrics of a compact manifold. In particular, we prove that nonproperness entails the presence of lightlike geodesic…

Differential Geometry · Mathematics 2007-05-23 Pierre Mounoud

In this paper, we establish a number of results about the topology of the leaves of a closed singular Riemannian foliation $(M,\fol)$. If $M$ is simply connected, we prove that the leaves are finitely covered by nilpotent spaces, and…

Differential Geometry · Mathematics 2022-04-01 Marco Radeschi , Elahe Khalili Samani

Let $f:M\to M$ be a dynamically coherent partially hyperbolic diffeomorphism whose center foliation has all its leaves compact. We prove that if the unstable bundle of $f$ is one-dimensional, then the volume of center leaves must be bounded…

Dynamical Systems · Mathematics 2019-01-01 Verónica De Martino , Santiago Martinchich

We study Lie foliations on compact manifolds, in case the Lie group is compact. Our main results improve Tischler classical result on the existence of fibration and, as an application, we study the case the manifold has an amenable…

Geometric Topology · Mathematics 2010-07-16 Marcelo Tavares

We give a classification for connected complete locally irreducible Riemannian manifolds with nonpositive curvature operator, which admit a nonzero closed or co-closed conformal Killing $L^{2}-$form. Moreover, we prove vanishing theorems…

Differential Geometry · Mathematics 2017-03-29 Sergey Stepanov , Irina Tsyganok

We show geodesic completeness of certain compact locally symmetric pseudo-Riemannian manifolds of signature $(2,n)$. Our model space $\mathbf{X}$ is a $1$-connected, indecomposable symmetric space of signature $(2,n)$, that admits a unique…

Differential Geometry · Mathematics 2025-06-18 Malek Hanounah

In their 2012 paper, Bobadilla and Koll\'ar studied topological conditions which guarantee that a proper map of complex algebraic varieties is a topological or differentiable fibration. They also asked whether a certain finiteness property…

Algebraic Geometry · Mathematics 2022-06-20 Yongqiang Liu , Laurenţiu Maxim , Botong Wang

We discuss the rigidity (or lack thereof) imposed by different notions of having an abundance of zero curvature planes on a complete Riemannian 3-manifold. We prove a rank rigidity theorem for complete 3-manifolds, showing that having…

Differential Geometry · Mathematics 2017-12-29 Renato G. Bettiol , Benjamin Schmidt

We consider a $3$-manifold $M$ equipped with nondegenerate contact form $\lambda$ and compatible almost complex structure $J$. We show that if the data $(M, \lambda, J)$ admits a stable finite energy foliation, then for a generic choice of…

Symplectic Geometry · Mathematics 2019-03-20 Joel W. Fish , Richard Siefring

We extend Beem's three completeness notions -- finite compactness, timelike Cauchy completeness, and Condition A -- originally defined for spacetimes, to Lorentzian length spaces and study their relationships. We prove that finite…

Differential Geometry · Mathematics 2026-02-04 Keita Takahashi