Is it correct that for any uniformly, independently chosen vectors $r,s \in \mathbb{Z}_2^m$ and for any $0 \neq D \in \mathbb{Z}_2^{m \times m}$, we have that $Pr_{r,s}\left[r^T\cdot D \cdot s \neq 0 \right] \geq \frac{1}{4}$? If so, how would I go about proving this?
Thanks!