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In this paper we use a dynamical approach to prove some new divergence theorems on complete non-compact Riemannian manifolds.

Differential Geometry · Mathematics 2016-12-28 Ítalo Melo , Enrique Pujals

In the paper we study the existence of balanced metrics of Hodge-Riemann type on non-K\"ahler complex manifolds. We first find some general obstructions, for instance that a Hodge-Riemann balanced manifold of complex dimension $n$ has to be…

Differential Geometry · Mathematics 2026-02-04 Anna Fino , Asia Mainenti

In this thesis, we study cohomological properties of non-K\"ahler manifolds. In particular, we are concerned in investigating the cohomology of compact (almost-)complex manifolds, and of manifolds endowed with special structures, e.g.,…

Differential Geometry · Mathematics 2013-02-05 Daniele Angella

In this article, we study complete pseudo-Riemannian manifolds whose cone admits a parallel symmetric 2-tensorfield. The situation splits in three cases: nilpotent, decomposable or complex Riemannian. In the complex Riemannian and…

Differential Geometry · Mathematics 2010-11-09 Pierre Mounoud

We construct homogeneous flat pseudo-Riemannian manifolds with non-abelian fundamental group. In the compact case, all homogeneous flat pseudo-Riemannian manifolds are complete and have abelian linear holonomy group. To the contrary, we…

Differential Geometry · Mathematics 2014-12-01 Oliver Baues , Wolfgang Globke

For k at least 2, we exhibit complete k-curvature homogeneous neutral signature pseudo-Riemannian manifolds which are not locally affine homogeneous (and hence not locally homogeneous). The curvature tensor of these manifolds is modeled on…

Differential Geometry · Mathematics 2007-05-23 Peter Gilkey , Stana Nikcevic

We develop a unifed theory to study geometry of manifolds with different holonomy groups. They are classified by (1) real, complex, quaternion or octonion number they are defined over and (2) being special or not. Specialty is an…

Differential Geometry · Mathematics 2007-05-23 Naichung Conan Leung

In this paper, we study the topology of complete noncompact Riemannian manifolds with asymptotically nonnegative Ricci curvature. We show that a complete noncompact manifold with asymptoticaly nonnegative Ricci curvature and sectional…

Differential Geometry · Mathematics 2008-09-29 Bazanfare Mahaman

Compact pseudo-Riemannian manifolds that have parallel Weyl tensor without being conformally flat or locally symmetric are known to exist in infinitely many dimensions greater than 4. We prove some general topological properties of such…

Differential Geometry · Mathematics 2011-06-07 Andrzej Derdzinski , Witold Roter

We provide uniqueness results for compact minimal submanifolds in a large class of Riemannian manifolds of arbitrary dimension. In the case compact and Cartan-Hadamard manifolds we obtain general results for these submanifolds. Several…

Differential Geometry · Mathematics 2016-06-23 R. M. Rubio , J. J. Salamanca

In the present article the geometry of semi-Riemannian manifolds with nonholonomic constraints is studied. These manifolds can be considered as analogues to the sub-Riemannian manifolds, where the positively definite metric is substituted…

Differential Geometry · Mathematics 2009-01-13 Anna Korolko , Irina Markina

In this article, we consider an orthogonal decomposition of the traceless part of the Ricci tensor of a compact Riemannian manifold and study its application to the geometry of compact almost Ricci solitons. In addition, we consider an…

Differential Geometry · Mathematics 2023-02-07 Sergey E. Stepanov , Josef Mikes , Irina I. Tsyganok

We descrive examples of metrics in the conformal class $[g]$ on complete conformally flat Riemannian manifolds $(M,g].$ These metrics have a constant scalar curvature and an harmonic curvature with non parallel Ricci tensor.

Differential Geometry · Mathematics 2007-05-23 A. Raouf Chouikha

This paper is an adaptation of a chapter from an upcoming monograph on noncommutative geometry and quantum groups. We present examples of non compact quantum groups which are deformations of low dimensional Lie groups. The paper is of…

Operator Algebras · Mathematics 2009-12-14 W. Pusz , P. M. Soltan

We give several explicit examples of compact manifolds with a $1$-parameter family of almost complex structures having arbitrarily small Nijenhuis tensor in the $C^0$-norm. The $4$-dimensional examples possess no complex structure, whereas…

Differential Geometry · Mathematics 2021-10-15 Luis Fernandez , Tobias Shin , Scott O. Wilson

We give a partial account of some problems concerning cohomological invariants and metric properties of complex non-K\"ahler manifolds.

Differential Geometry · Mathematics 2026-02-04 Daniele Angella , Nicoletta Tardini

We give obstructions for a noncompact manifold to admit a complete Riemannian metric with (nonuniformly) positive scalar curvature. We treat both the finite volume and infinite volume cases.

Differential Geometry · Mathematics 2025-09-23 John Lott

Almost paracontact manifolds of an odd dimension having an almost paracomplex structure on the paracontact distribution are studied. The components of the fundamental (0,3)-tensor, derived by the covariant derivative of the structure…

Differential Geometry · Mathematics 2019-08-07 Mancho Manev , Veselina Tavkova

We construct lattices on six dimensional not completely solvable almost abelian Lie groups, for which the Mostow condition does not hold. For the corresponding compact quotients, we compute the de Rham cohomology (which does not agree in…

Differential Geometry · Mathematics 2012-06-27 Sergio Console , Maura Macrì

As a generalization of anti-invariant Riemannian submersions, we introduce anti-invariant Riemannian maps from almost Hermitian manifolds to Riemannian manifolds. We give examples and investigate the geometry of foliations which are arisen…

Differential Geometry · Mathematics 2012-10-02 Bayram Sahin