English
Coinduced respects supremum over sets: coinduced f (sSup s) = sSup (image (coinduced f) s).
Русский
Коиндуцированная по f сохраняет sSup над множеством: coinduced f (sSup s) = sSup (image (coinduced f) s).
LaTeX
$$$\operatorname{coinduced} f (\mathrm{sSup} s) = \mathrm{sSup} (\mathrm{image}(\operatorname{coinduced} f) s)$$$
Lean4
@[simp]
theorem coinduced_sSup {s : Set (TopologicalSpace α)} :
TopologicalSpace.coinduced f (sSup s) = sSup ((TopologicalSpace.coinduced f) '' s) := by
rw [sSup_eq_iSup', sSup_image', coinduced_iSup]