English
The epi_iff_surjective_on_stonean holds for Condensed sets and Stonean objects.
Русский
Справедливостe epi на Stonean: эпи-ограничения эквивалентны сюръективности на каждом Stonean объекте.
LaTeX
$$$\\mathrm{epi_iff_surjective_on_stonean}(f) \\iff \\forall S:\\mathrm{Stonean},\\; \\mathrm{Surjective}((f)_{S})$$$
Lean4
theorem epi_iff_locallySurjective_on_compHaus :
Epi f ↔
∀ (S : CompHaus) (y : ToType (Y.val.obj ⟨S⟩)),
(∃ (S' : CompHaus) (φ : S' ⟶ S) (_ : Function.Surjective φ) (x : ToType (X.val.obj ⟨S'⟩)),
f.val.app ⟨S'⟩ x = Y.val.map ⟨φ⟩ y) :=
by
rw [← isLocallySurjective_iff_epi', coherentTopology.isLocallySurjective_iff, regularTopology.isLocallySurjective_iff]
simp_rw [((CompHaus.effectiveEpi_tfae _).out 0 2 :)]