# nLab vertical vector field

Let $\pi :P\to X$ be a bundle in the category Diff of smooth manifolds. A vector field $v\in \Gamma \left(P\right)$ is vertical with respect to this bundle if it is in the kernel of the differential $d\pi :TP\to TX$.

Revised on April 5, 2013 13:38:54 by Urs Schreiber (82.169.65.155)