Results 21 to 30 of about 1,005 (125)
The Classification of Flat Solvmanifolds [PDF]
This paper contains a complete algebraic characterization of the fundamental groups of flat solvmanifolds. This characterization is in terms of finite integral representations of free abelian groups and the associated cohomology. A classification of compact flat solvmanifolds follows, and a list of all compact flat solvmanifolds of dimensions 3, 4, and
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On low-dimensional solvmanifolds [PDF]
105 pages, 36 tables; ad v4: References to other papers ...
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Formality and the Lefschetz property in symplectic and cosymplectic geometry
We review topological properties of K\"ahler and symplectic manifolds, and of their odd-dimensional counterparts, coK\"ahler and cosymplectic manifolds. We focus on formality, Lefschetz property and parity of Betti numbers, also distinguishing the simply-
Bazzoni, Giovanni +2 more
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Symplectic harmonicity and generalized coeffective cohomologies [PDF]
Relations between the symplectically harmonic cohomology and the coeffective cohomology of a symplectic manifold are obtained. This is achieved through a generalization of the latter, which in addition allows us to provide a coeffective version of the ...
Ugarte, Luis, Villacampa, Raquel
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Pseudo-Riemannian Sasaki solvmanifolds
We study a class of left-invariant pseudo-Riemannian Sasaki metrics on solvable Lie groups, which can be characterized by the property that the zero level set of the moment map relative to the action of some one-parameter subgroup $\{\exp tX\}$ is a normal nilpotent subgroup commuting with $\{\exp tX\}$, and $X$ is not lightlike.
Conti, D, Rossi, FA, Segnan Dalmasso, R
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Chern‐Simons forms of pseudo‐Riemannian homogeneity on the oscillator group
We consider forms of Chern‐Simons type associated to homogeneous pseudo‐Riemannian structures. The corresponding secondary classes are a measure of the lack of a homogeneous pseudo‐Riemannian space to be locally symmetric. In the present paper, we compute these forms for the oscillator group and the corresponding secondary classes of the compact ...
P. M. Gadea, J. A. Oubiña
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Formality and hard Lefschetz property of aspherical manifolds [PDF]
For a Lie group $G=\R^{n}\ltimes_{\phi}\R^{m}$ with the semi-simple action $\phi:\R^{n}\to {\rm Aut}(\R^{m})$, we show that if $\Gamma$ is a finite extension of a lattice of $G$ then $K(\Gamma, 1)$ is formal.
Kasuya, Hisashi
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Tessellations of solvmanifolds [PDF]
Let A A be a closed subgroup of a connected, solvable Lie group G G , such that the homogeneous space A ∖ G A\backslash G is simply connected. As a special case of a theorem of C. T. C. Wall, it is known that every tessellation A ∖ G /
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Cohomologically Kähler manifolds with no Kähler metrics
We show some examples of compact symplectic solvmanifolds, of dimension greater than four, which are cohomologically Kähler and do not admit Kähler metric since their fundamental groups cannot be the fundamental group of any compact Kähler manifold. Some of the examples that we study were considered by Benson and Gordon (1990).
Marisa Fernández +2 more
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Warped product Einstein metrics on homogeneous spaces and homogeneous Ricci solitons [PDF]
In this paper we consider connections between Ricci solitons and Einstein metrics on homogeneous spaces. We show that a semi-algebraic Ricci soliton admits an Einstein one-dimensional extension if the soliton derivation can be chosen to be normal.
He, Chenxu +2 more
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