English
If F reflects isomorphisms and preserves epimorphisms and monomorphisms and D is balanced, then C is balanced.
Русский
Если F отражает изоморфизмы и сохраняет эпиморфизмы и мономорфизмы, а D сбалансирована, то C также сбалансирована.
LaTeX
$$$\\text{Balanced}(D) \\,\\wedge\\, F.ReflectsIsomorphisms \\wedge F.\\PreservesEpimorphisms \\wedge F.\\PreservesMonomorphisms \\Rightarrow \\text{Balanced}(C).$$$
Lean4
theorem balanced_of_preserves (F : C ⥤ D) [F.ReflectsIsomorphisms] [F.PreservesEpimorphisms] [F.PreservesMonomorphisms]
[Balanced D] : Balanced C where
isIso_of_mono_of_epi f _
_ := by
rw [← isIso_iff_of_reflects_iso (F := F)]
exact isIso_of_mono_of_epi _