English
If f1 and f2 agree on the circle, their circle averages are equal (congruence on sphere).
Русский
Если f1 и f2 согласуются на окружности, их средние совпадают (конгруэнтность на сфере).
LaTeX
$$$circleAverage\ f_1\ c\ R = circleAverage\ f_2\ c\ R\;\text{если }\;f_1=f_2\text{ на окружности}$$$
Lean4
/-- Circle averages commute with scalar multiplication. -/
theorem circleAverage_smul : circleAverage (a • f) c R = a • circleAverage f c R :=
by
unfold circleAverage
have := SMulCommClass.symm ℝ 𝕜 E
rw [smul_comm]
simp [intervalIntegral.integral_smul]