  Let $n \geq 3$ and $R_{abcd}$ be a $(4,0)$ sectionally positive
curvature-type tensor (a tensor possessing all the local symmetries of the
$(4,0)$ curvature tensor). Then there exists a metric tensor $g_{ab}$ such that
$R_{abcd}\; g^{bd} = g_{ac} \lambda$ for some $\lambda$. Furthermore, $g_{ab}$
is unique up to a constant factor.
