English
For any I and f, the equality in map_spanIntNorm holds: map f (spanNorm R I) = span ( image of intNorm through f over I ).
Русский
Для данного I и отображения f выполняется равенство: map f (spanNorm R I) = span (image (intNorm) через f на I).
LaTeX
$$$$\operatorname{map}(f, \operatorname{spanNorm}(R,I)) = \operatorname{span}\Big( f\circ \operatorname{Algebra.intNorm}(R,S) '' (I) \Big). $$$$
Lean4
theorem map_spanIntNorm (I : Ideal S) {T : Type*} [Semiring T] (f : R →+* T) :
map f (spanNorm R I) = span (f ∘ Algebra.intNorm R S '' (I : Set S)) :=
by
rw [spanNorm]
nth_rw 2 [map]
simp [map_span, Set.image_image]