# Contents

## Idea

For $E_1, E_2 \to X$ two vector bundles, their direct sum over $X$, also called their Whitney sum, is the vector bundle $E_1 \oplus E_2 \to X$ whose fiber over any $x \in X$ is the direct sum of vector spaces of the fibers of $E_1$ and $E_2$.

Revised on July 12, 2013 19:10:10 by Urs Schreiber (82.113.121.27)