English
If mk F v hv ≠ mk F w hw, then cross (mk F v hv) (mk F w hw) equals mk F (crossProduct v w) (proof_of_nonzero).
Русский
Если mk F v hv не равно mk F w hw, то cross( mk F v hv, mk F w hw ) = mk F (crossProduct v w) некое_доказательство_не нулю.
LaTeX
$$$\\text{cross}(\\text{mk}(F,v,hv), \\text{mk}(F,w,hw)) = \\text{mk}(F, crossProduct(v,w), h)$$$
Lean4
theorem cross_mk_of_ne {v w : Fin 3 → F} (hv : v ≠ 0) (hw : w ≠ 0) (h : mk F v hv ≠ mk F w hw) :
cross (mk F v hv) (mk F w hw) = mk F (crossProduct v w) (mt (mk_eq_mk_iff_crossProduct_eq_zero hv hw).mpr h) := by
rw [cross_mk_of_cross_ne_zero]