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There are five six-dimensional nilpotent Lie groups G, which do not admit neither symplectic, nor complex structures and, therefore, can be neither almost pseudo-Kahler, nor almost Hermitian. In this work, these Lie groups are being…

Differential Geometry · Mathematics 2020-01-10 Nikolay K. Smolentsev

We classify invariant complex structures on 6-dimensional nilmanifolds up to equivalence. As an application, the behaviour of the associated Fr\"olicher sequence is studied as well as its relation to the existence of strongly Gauduchon…

Differential Geometry · Mathematics 2014-10-13 Manuel Ceballos , Antonio Otal , Luis Ugarte , Raquel Villacampa

In this note, we explore various cohomological invariants on double complexes with the aim of finding their decomposition into irreducible parts, which are of square and zigzag shape. By studying the growth rate of the number of invariants…

Differential Geometry · Mathematics 2026-03-24 Victor Chen

We study the six-dimensional solvmanifolds that admit complex structures of splitting type classifying the underlying solvable Lie algebras. In particular, many complex structures of this type exist on the Nakamura manifold $X$, and they…

Differential Geometry · Mathematics 2017-12-12 Daniele Angella , Antonio Otal , Luis Ugarte , Raquel Villacampa

We propose the study and description of the structure of complex Lie algebras with nilradical a nilpotent Lie algebra of type 2 by using sl2(C)-representation theory. Our results will be applied to review the classification given in [1] (J.…

Rings and Algebras · Mathematics 2016-11-26 Pilar Benito , Daniel de-la-Concepción

Finite-order invariants of knots in arbitrary 3-manifolds (including non-orientable ones) are constructed and studied by methods of the topology of discriminant sets. Obstructions to the integrability of admissible weight systems to…

Geometric Topology · Mathematics 2016-09-07 Victor A. Vassiliev

We introduce the notion of a manifold admitting a simple compact Cartan 3-form $\om^3$. We study algebraic types of such manifolds specializing on those having skew-symmetric torsion, or those associated with a closed or coclosed 3-form…

Differential Geometry · Mathematics 2013-04-04 Hong Van Le

Let $M= G/\Gamma$ be a compact nilmanifold endowed with an invariant complex structure. We prove that, on an open set of any connected component of the moduli space ${\cal C} ({\frak g})$ of invariant complex structures on $M$, the…

Differential Geometry · Mathematics 2007-05-23 S. Console , A. Fino

The class of the hypercomplex pseudo-Hermitian manifolds is considered. The flatness of the considered manifolds with the 3 parallel complex structures is proved. Conformal transformations of the metrics are introduced. The conformal…

Differential Geometry · Mathematics 2012-03-27 Kostadin Gribachev , Mancho Manev , Stancho Dimiev

We introduce the concept of 3-Lie-Rinehart superalgebra and systematically describe a cohomology complex by considering coefficient modules. Furthermore, we study the relationships between a Lie-Rinehart superalgebra and its induced…

Rings and Algebras · Mathematics 2020-10-06 Abdelkader Ben Hassine , Taoufik Chtioui , Sami Mabrouk , Sergei Silvestrov

We describe representations of certain superconformal algebras in the semi-infinite Weil complex related to the loop algebra of a complex finite-dimensional Lie algebra and in the semi-infinite cohomology. We show that in the case where the…

Algebraic Geometry · Mathematics 2007-05-23 Elena Poletaeva

In this work we study the existence of invariant almost complex structures on real flag manifolds associated to split real forms of complex simple Lie algebras. We show that, contrary to the complex case where the invariant almost complex…

Differential Geometry · Mathematics 2017-08-04 Ana P. C. Freitas , Viviana del Barco , Luiz A. B. San Martin

We approach the classification of Lie bialgebra structures on simple Lie algebras from the viewpoint of descent and non-abelian cohomology. We achieve a description of the problem in terms faithfully flat cohomology over an arbitrary ring…

Quantum Algebra · Mathematics 2019-03-25 Seidon Alsaody , Arturo Pianzola

This paper can be considered as an extension to our paper [On symplectically harmonic forms on six-dimensional nilmanifolds, Comment. Math. Helv. 76 (2001), n 1, 89-109]. Also, it contains a brief survey of recent results on symplectically…

Symplectic Geometry · Mathematics 2007-05-23 R. Ibáñez , Yu. Rudyak , A. Tralle , L. Ugarte

The study of quasi-K\"ahler Chern-flat almost Hermitian manifolds is strictly related to the study of anti-bi-invariant almost complex Lie algebras. In the present paper we show that quasi-K\"ahler Chern-flat almost Hermitian structures on…

Differential Geometry · Mathematics 2011-01-11 Antonio J. Di Scala , Jorge Lauret , Luigi Vezzoni

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

We construct geometric examples of N-differential graded algebras such as the algebra of differential forms of depth $N$ on an affine manifold, and $N$-flat covariant derivatives.

Differential Geometry · Mathematics 2016-08-16 Mauricio Angel , Rafael Díaz

It is known that there exist complex solvmanifolds $(\Gamma\backslash G,J)$ whose canonical bundle is trivialized by a holomorphic section which is not invariant under the action of $G$. The main goal of this article is to classify the…

Differential Geometry · Mathematics 2025-06-26 Alejandro Tolcachier

We study generalized complex structures and $T$-duality (in the sense of Bouwknegt, Evslin, Hannabuss and Mathai) on Lie algebras and construct the corresponding Cavalcanti and Gualtieri map. Such a construction is called "Infinitesimal…

Differential Geometry · Mathematics 2018-07-04 Viviana del Barco , Lino Grama , Leonardo Soriani

We show an integrality of the quantum SU(2)-invariant associated with a non-trivial first cohomology class modulo two.

Geometric Topology · Mathematics 2007-05-23 Hitoshi Murakami