English
The linear part of the signed distance corresponds to the inner product with the normalized direction.
Русский
Линейная часть подписанного расстояния связана с inner-произведением по нормализованному направлению.
LaTeX
$$$$\operatorname{signedDist}(v)\text{ is linear in } w,\text{ with } (signedDist(v)).linear = \langle -\operatorname{normalize}(v), w\rangle.$$$$
Lean4
theorem signedDist_apply_linear : (signedDist v p).linear = innerₗ V (normalize v) :=
by
change (innerₗ V (normalize v)).comp (LinearMap.id - 0) = _
simp