English
If α has a Mod structure, then applying mod to the images of a and b under some preserves the mod of a and b: some(a) % some(b) = some(a % b).
Русский
Пусть у α есть структура Mod. Тогда модуль от образов a и b через some сохраняет модуль: some(a) % some(b) = some(a % b).
LaTeX
$$$$ \mathrm{some}(a) \bmod \mathrm{some}(b) = \mathrm{some}(a \bmod b). $$$$
Lean4
theorem some_mod_some [Mod α] (a b : α) : some a % some b = some (a % b) := by simp [mod_def]