Petrov Types for the Weyl Tensor via the Riemannian-to-Lorentzian Bridge

Amir Babak Aazami

We analyze oriented Riemannian 4-manifolds whose Weyl tensors $W$ satisfy the conformally invariant condition $W(T,\cdot ,\cdot ,T)=0$ for some nonzero vector $T$. While this can b…