3D-Darboux motions in 4-dimensional Euclidean space.
The aim of this paper is to give an easy explicit description of 3-K-contact structures on SO(3)-principal fibre bundles over Wolf quaternionic Kähler manifolds.
We study 3-submersions from a QR-hypersurface of a quaternionic Kähler manifold onto an almost quaternionic hermitian manifold. We also prove the non-existence of quaternionic submersions between quaternionic Kähler manifolds which are not locally hyper-Kähler.
On a 4-dimensional anti-Kähler manifold, its zero scalar curvature implies that its Weyl curvature vanishes and vice versa. In particular any 4-dimensional anti-Kähler manifold with zero scalar curvature is flat.
The aim of this article is to answer a question posed by J. Oprea in his talk at the Workshop "Homotopy and Geometry".
We investigate ∇-flat and pointwise-∇-flat functions on affine and Riemannian manifolds. We show that the set of all ∇-flat functions on (M,∇) is a ring which has interesting properties similar to the ring of polynomial functions.
A Lie version of Turaev’s -Frobenius algebras from 2-dimensional homotopy quantum field theory is proposed. The foundation for this Lie version is a structure we call a -quasi-Frobenius Lie algebra for a finite dimensional Lie algebra. The latter consists of a quasi-Frobenius Lie algebra together with a left -module structure which acts on via derivations and for which is -invariant. Geometrically, -quasi-Frobenius Lie algebras are the Lie algebra structures associated to symplectic...