English
For two division semirings R and S with a module structure on M, birkhoffAverage_R equals birkhoffAverage_S for all f,g,n,x; i.e., the average does not depend on the ambient coefficient ring when comparing these two settings.
Русский
Для двух полускольных колец R и S с модулем M среднее Биркхоффа не зависит от выбранного кольца в рамках сопоставления birkhoffAverage: birkhoffAverage_R = birkhoffAverage_S.
LaTeX
$$$\forall R,S,\ birkhoffAverage(R,f,g,n,x) = birkhoffAverage(S,f,g,n,x).$$$
Lean4
theorem birkhoffAverage_congr_ring (S : Type*) [DivisionSemiring S] [Module S M] (f : α → α) (g : α → M) (n : ℕ)
(x : α) : birkhoffAverage R f g n x = birkhoffAverage S f g n x :=
map_birkhoffAverage R S (AddMonoidHom.id M) f g n x