5 papers
A Singularity Theorem for Twistor Spinors
Florin Belgun, Nicolas Ginoux, Hans-Bert Rademacher
We study spin structures on orbifolds. In particular, we show that if the singular set has codimension greater than 2, an orbifold is spin if and only if its smooth part is. On com…
Automorphism groups of normal CR 3-manifolds
Florin Alexandru Belgun
We classify the normal CR structures on and their automorphism groups. Together with [3], this closes the classification of normal CR structures on contact 3-manifolds. We gi…
Null-geodesics in complex conformal manifolds and the LeBrun correspondence
F. A. Belgun
In the complex-Riemannian framework we show that a conformal manifold containing a compact, simply-connected, null-geodesic is conformally flat. In dimension 3 we use the LeBrun co…
Normal CR structures on compact 3-manifolds
F. A. Belgun
We study normal CR compact manifolds in dimension 3. For a choice of a CR Reeb vector field, we associate a Sasakian metric on them, and we classify those metrics. As a consequence…
On the Weyl tensor of a self-dual complex 4-manifold
F. A. Belgun
We study complex 4-manifolds with holomorphic self-dual conformal structures, and we obtain an interpretation of the Weyl tensor of such a manifold as the projective curvature of a…