English
The forward stereographic projection stereoToFun v is ContDiffOn on the domain where the inner product condition holds, and this continues to hold after composition with the orthogonal projection.
Русский
Прямое стереографическое проецирование stereoToFun v гладко на области, где выполнено условие по скалярному продукту, и это сохраняется после композиции с ортогональной проекцией.
LaTeX
$$ContDiffOn Real n (stereoToFun v) (setOf x => Ne (ContinuousLinearMap.funLike.coe (ContinuousLinearMap.funLike.coe (innerSL Real) v) x) 1)$$
Lean4
theorem continuousOn_stereoToFun : ContinuousOn (stereoToFun v) {x : E | innerSL _ v x ≠ (1 : ℝ)} :=
(contDiffOn_stereoToFun (n := 0)).continuousOn