English
If f: V →ₗ[K] V₂ is injective and the dimensions finrank K V and finrank K V₂ agree, then f extends to a linear isomorphism V ≃ₗ[K] V₂ which agrees with f on every vector.
Русский
Пусть f: V →ₗ[K] V₂ инъективно и размерности финитно равны; тогда f можно продолжить до линейного изоморфизма V ≃ₗ[K] V₂, который совпадает с f на каждом элементе.
LaTeX
$$$\exists e: V \cong_K V_2\quad \text{с } \forall x\in V:\ e(x) = f(x)$$$
Lean4
/-- Given `c = lineMap a b r`, `a < c`, the point `(c, f c)` is non-strictly above the
segment `[(a, f a), (b, f b)]` if and only if `slope f a b ≤ slope f a c`. -/
theorem lineMap_le_map_iff_slope_le_slope_left (h : 0 < r * (b - a)) :
lineMap (f a) (f b) r ≤ f c ↔ slope f a b ≤ slope f a c :=
map_le_lineMap_iff_slope_le_slope_left (E := Eᵒᵈ) (f := f) (a := a) (b := b) (r := r) h