Let $(M,g)$ be a spin manifold with spinors bundle $\Sigma$, a spinorial connection is an operator:
$$\nabla : \Sigma \rightarrow \Sigma$$
$$\nabla(f \psi)= (df)^* .\psi + f \nabla \psi$$
with $\psi$, a spinor and $f$ a smooth function.
What are the properties of the spinorial connections?