# Problem Sheet P

- Problem 1 is a fun™ computation in local coordinates.
- Problem 2 gives another viewpoint on the torsion tensor of a connection (compare this to the Bianchi Identity $ d^{ \nabla^{ \operatorname{Hom}}} (R^{ \nabla} ) = 0$.)
- Problem 3 asks you to prove the second additional curvature symmetry of torsion-free connections that we skipped in class.
- Problem 4 identifies the Levi-Civita connection of the round metric on $S^m$.
- Problem 5 introduces
*Killing fields* - Problem 6 asks you to show that if $ \varphi \colon M \to N$ is an isometric map then for $\xi \in T_{ \varphi(p)}N$, the tangential component $ \xi^\top$ is simply the orthogonal projection of $\xi$ onto $D \varphi(p)(T_pM)$.
- Problem 7 is about Riemannian coverings, and requires you to know a little bit of covering space theory in order to solve it.
- Problem 8 is about invariant metrics on homogeneous spaces.
- Problem 9 completes our discussion of holonomy groups.
- Problem 10 studies bi-invariant Riemannian metrics on Lie groups.
- Problem 11 identifies the Levi-Civita connection of a Lie group endowed with a bi-invariant Riemannian metric.

Comments and questions?