  We give a characterization of Whitney forms on an $n$-simplex $\sigma$ and
prove that for every real valued simplicial $k$-cochain $c$ on $\sigma$, the
form $Wc$ is the unique differential $k$-form $\varphi$ on $\sigma$ with affine
coefficients that pulls back to a constant form of degree $k$ on every $k$-face
$\tau$ of $\sigma$ and satisfies $\int_{\tau} \varphi = <c,\tau>$.
