English
In the previous construction, the second component of the pair produced by unitsSMulGroup is exactly the second component of the image of g under the complement-related equivalence.
Русский
Во второй компоненте пары из unitsSMulGroup совпадает второй элемент изображения g через соответствующее отображение-комплемента.
LaTeX
$$$\\mathrm{snd}\\big(\\mathrm{unitsSMulGroup}(\\varphi,d,u,g)\\big) = ((d^{\\mathrm{compl}}(u)).\\mathrm{equiv} \\; g).2.$$$
Lean4
theorem unitsSMulGroup_snd (u : ℤˣ) (g : G) : (unitsSMulGroup φ d u g).2 = ((d.compl u).equiv g).2 := by
rcases Int.units_eq_one_or u with rfl | rfl <;> rfl