English
The range of the image operator equals the power set of the range of f: range (image f) = P(range f).
Русский
Диапазон оператора образа равен множеству подмножеств диапазона функции: range(image f) = P(range f).
LaTeX
$$$ \\mathrm{range}(\\mathrm{image}(f)) = \\mathcal{P}(\\mathrm{range}(f)). $$$
Lean4
theorem range_image (f : α → β) : range (image f) = 𝒫 range f :=
ext fun _ => subset_range_iff_exists_image_eq.symm