For any two points \( P, Q \in \mathbb{R}^3 \), let \( \vec{P, Q} \) denote the vector from the point \( P \) to the point \( Q \) and let \( d(P, Q) \) denote the length of \( \vec{P, Q} \). Let \( F: \mathbb{R}^3 \to \mathbb{R}^3 \) be a linear transformation such that