A short proof of the Poincare Lemma

I would like to share a concise proof of the Poincaré Lemma using the flow of a radial vector field. Theorem (Poincaré Lemma) Assume that a smooth ##k##-form $\omega = \sum_{i_1 < \dots < i_k} \omega_{i_1 \dots i_k} (x) dx^{i_1} \wedge \dots \wedge dx^{i_k}$ is defined in a... Read more