48 citations · 81 across the 3 of their papers we have counts for
12 papers · 1 filter
Nearly Kaehler and nearly parallel G_2-structures on spheres
Thomas Friedrich
In some other context, the question was raised how many nearly Kähler structures exist on the sphere equipped with the standard Riemannian metric. In this short note, we prov…
On types of non-integrable geometries
Thomas Friedrich
We study the types of non-integrable -structures on Riemannian manifolds. In particular, geometric types admitting a connection with totally skew-symmetric torsion are…
Almost contact manifolds, connections with torsion and parallel spinors
Thomas Friedrich, Stefan Ivanov
We classify locally homogeneous quasi-Sasakian manifolds in dimension five that admit a parallel spinor of algebraic type with respect to the unique connection $…
Eigenvalue estimates of the Dirac operator depending on the Ricci tensor
Thomas Friedrich, Klaus-Dieter Kirchberg
We prove a new lower bound for the first eigenvalue of the Dirac operator on a compact Riemannian spin manifold by refined Weitzenböck techniques. It applies to manifolds with harm…
New Solutions of the Einstein-Dirac Equation in Dimension n=3
Thomas Friedrich
The aim of this short note is to announce the existence of a one-parameter family of left-invariant metrics on admitting WK-spinors. This family contains the two non-Einstein…
Weak -Structures on 16-dimensional Riemannian Manifolds
Thomas Friedrich
The aim of the present paper is the investigation of -structures on 16-dimensional manifolds from the point of view of topology as well as holonomy theory. First we constr…