Results 11 to 20 of about 334 (56)

Abelian simply transitive affine groups of symplectic type [PDF]

open access: yes, 2001
We construct a model space $C(\gsp(\bR^{2n}))$ for the variety of Abelian simply transitive groups of affine transformations of type ${\rm Sp}(\bR^{2n})$.
Baues, Oliver, Cortes, Vicente
core   +2 more sources

SO(3)-Structures on 8-manifolds [PDF]

open access: yes, 2011
We study Riemannian 8-manifolds with an infinitesimal action of SO(3) by which each tangent space breaks into irreducible spaces of dimensions 3 and 5.
Chiossi, Simon G., Maciá, Óscar
core   +1 more source

The even Clifford structure of the fourth Severi variety

open access: yesComplex Manifolds, 2015
TheHermitian symmetric spaceM = EIII appears in the classification of complete simply connected Riemannian manifolds carrying a parallel even Clifford structure [19].
Parton Maurizio, Piccinni Paolo
doaj   +1 more source

A Nearly Quaternionic Structure on SU(3)

open access: yes, 2009
It is shown that the compact Lie group SU(3) admits an Sp(2)Sp(1)-structure whose distinguished 2-forms $\omega_1,\omega_2,\omega_3$ span a differential ideal. This is achieved by first reducing the structure further to a subgroup isomorphic to SO(3)
Besse   +15 more
core   +1 more source

The second Betti number of hyperk\"ahler manifolds [PDF]

open access: yes, 2015
Let $M$ be a compact irreducible hyperkahler manifold, from Bogomolov inequality [V1] we obtain forbidden values of the second Betti number $b_2$ in arbitrary dimension.
Kurnosov, Nikon
core  

Parallelizations on products of spheres and octonionic geometry

open access: yesComplex Manifolds, 2019
A classical theoremof Kervaire states that products of spheres are parallelizable if and only if at least one of the factors has odd dimension. Two explicit parallelizations on Sm × S2h−1 seem to be quite natural, and have been previously studied by the ...
Parton Maurizio, Piccinni Paolo
doaj   +1 more source

On the cohomology of some exceptional symmetric spaces

open access: yes, 2016
This is a survey on the construction of a canonical or "octonionic K\"ahler" 8-form, representing one of the generators of the cohomology of the four Cayley-Rosenfeld projective planes.
A. Borel   +20 more
core   +1 more source

On quaternionic functions [PDF]

open access: yes, 2013
Several sets of quaternionic functions are described and studied.
Dolbeault, Pierre
core   +2 more sources

Hyperk\"ahler torsion structures invariant by nilpotent Lie groups

open access: yes, 2001
We study HKT structures on nilpotent Lie groups and on associated nilmanifolds. We exhibit three weak HKT structures on $\R^8$ which are homogeneous with respect to extensions of Heisenberg type Lie groups.
Anna Fino   +20 more
core   +1 more source

Collections of parabolic orbits in homogeneous spaces, homogeneous dynamics and hyperkahler geometry

open access: yes, 2016
Let $M$ be a hyperk\"ahler manifold with $b_2(M)\geq 5$. We improve our earlier results on the Morrison-Kawamata cone conjecture by showing that the Beauville-Bogomolov square of the primitive MBM classes (i.e.
Amerik, Ekaterina, Verbitsky, Misha
core   +1 more source

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