English
The torus integral is linear with respect to subtraction: torusIntegral(f - g) = torusIntegral(f) - torusIntegral(g).
Русский
Торо-интеграл линейен по отношению к вычитанию: torusIntegral(f - g) = torusIntegral(f) - torusIntegral(g).
LaTeX
$$$\operatorname{torusIntegral}(f-c,R) = \operatorname{torusIntegral}(f,R) - \operatorname{torusIntegral}(g,R)$$$
Lean4
theorem torusIntegral_sub (hf : TorusIntegrable f c R) (hg : TorusIntegrable g c R) :
(∯ x in T(c, R), f x - g x) = (∯ x in T(c, R), f x) - ∯ x in T(c, R), g x := by
simpa only [sub_eq_add_neg, ← torusIntegral_neg] using torusIntegral_add hf hg.neg