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In this note we study a new cohomology attached to a function along the leaves of complex foliations. We also explain how this cohomology depends on the function and we study a relative cohomology and a Mayer-Vietoris sequence related to…

Differential Geometry · Mathematics 2010-12-07 Cristian Ida

We investigate the $CR$ geometry of the orbits $M$ of a real form $G_0$ of a complex simple group $G$ in a complex flag manifold $X=G/Q$. We are mainly concerned with finite type, Levi non-degeneracy conditions, canonical $G_0$-equivariant…

Complex Variables · Mathematics 2010-12-20 Andrea Altomani , Costantino Medori , Mauro Nacinovich

The purpose of this paper is to study the canonical totally real foliations of CR-submanifolds in a locally conformal K\"{a}hler manifold.

Differential Geometry · Mathematics 2012-04-24 Gabriel Eduard Vilcu

We introduce a global Cauchy-Riemann($CR$)-invariant and discuss its behavior on the moduli space of $CR$-structures. We argue that this study is related to the Smale conjecture in 3-topology and the problem of counting complex structures.…

Differential Geometry · Mathematics 2007-05-23 Jih-Hsin Cheng

A semiholomorphic foliations of type (n, d) is a differentiable real manifold X of dimension 2n + d, foliated by complex leaves of complex dimension n. In the present work, we introduce an appropriate notion of pseudoconvexity (and…

Complex Variables · Mathematics 2014-04-29 Samuele Mongodi , Giuseppe Tomassini

For certain real hypersurfaces in the projective space, of signature (1,n), we study the filling problem for small deformations of the CR structure (the other signatures being well understood). We characterize the deformations which are…

Differential Geometry · Mathematics 2007-05-23 Olivier Biquard

We consider manifolds endowed with metric contact pairs for which the two characteristic foliations are orthogonal. We give some properties of the curvature tensor and in particular a formula for the Ricci curvature in the direction of the…

Differential Geometry · Mathematics 2011-10-31 G. Bande , D. E. Blair , A. Hadjar

We prove the algebraicity of smooth $CR$-mappings between algebraic Cauchy--Riemann manifolds. A generalization of separate algebraicity principle is established.

alg-geom · Mathematics 2008-02-03 R. A. Sharipov , A. B. Sukhov

We give an example of a compact Levi-flat CR 3-manifold with a positive-along-leaves CR line bundle which is not ample with respect to transversely infinitely differentiable CR sections. This example shows that we cannot improve the…

Complex Variables · Mathematics 2014-03-14 Masanori Adachi

For any compact Lie group G we discuss the relation of the equivariant Reidemeister and analytic torsion of G-manifolds with their G-CW structures.

dg-ga · Mathematics 2007-05-23 U. Bunke

The purpose of this paper is to study the canonical foliations of a quaternion CR-submanifold of an almost quaternion Kaehler product manifold.

Differential Geometry · Mathematics 2009-12-02 Gabriel Eduard Vilcu

For any flag manifold G/T we obtain an explicit expression of its Levi-Civita connection with respect to any invariant Riemannian metric.

Differential Geometry · Mathematics 2007-05-23 Anna Sakovich

In this paper we show some results on homogeneous CR manifolds, proved by introducing their associated CR algebras. In particular, we give different notions of nondegeneracy (generalizing the usual notion for the Levi form) which correspond…

Complex Variables · Mathematics 2009-02-18 Andrea Altomani , Costantino Medori

A parallel lightlike vector field on a Lorentzian manifold $X$ naturally defines a foliation $\mathcal{F}$ of codimension one. If either all leaves of $\mathcal{F}$ are compact or $X$ itself is compact admitting a compact leaf and the…

Differential Geometry · Mathematics 2010-10-12 Kordian Lärz

We define a complex whose cohomology group of order 1 contains the infinitesimal deformations of a Levi flat structure on a smooth manifold. In the case of real analytic Levi flat structures, this cohomology group is the product of the…

Complex Variables · Mathematics 2014-06-24 Paolo de Bartolomeis , Andrei Iordan

In this work, we find an equation that relates the Ricci curvature of a riemannian manifold $M$ and the second fundamental forms of two orthogonal foliations of complementary dimensions, $\mathcal{F}$ and $\mathcal{F}^{\bot}$, defined on…

Differential Geometry · Mathematics 2017-11-16 André de Oliveira Gomes , Eurípedes Carvalho da Silva

After reviewing manifold optimization techniques in applications like MIMO communication systems, phased array beamforming, radar, and control theory, we observed that the Complex Circle Manifold (CCM) is widely employed, yet its…

Optimization and Control · Mathematics 2025-08-12 Amirreza Tabrizi , Mohammad Hadi Mirmohammadi

A CR generic real analytic CR manifold M carries two families of Segre varieties and conjugate Segre varieties. We observe in this article that their complexifications give rise to two families of foliations of the complexification of M…

Complex Variables · Mathematics 2007-05-23 Joel Merker

We provide regularity results for CR-maps between real hypersurfaces in complex spaces of different dimension with a Levi-degenerate target. We address both the real-analytic and the smooth case. Our results allow immediate applications to…

Complex Variables · Mathematics 2020-06-15 Ilya Kossovskiy , Bernhard Lamel , Ming Xiao

We provide examples of foliations on the complex projective plane $\CP^2$ carrying positive foliated harmonic currents whose supports coincide with singular Levi-flats which, in turn, can be chosen real-analytic (but non-algebraic) or…

Dynamical Systems · Mathematics 2023-04-10 Mohamad Alkateeb , Julio Rebelo