English
If F creates colimits and G preserves colimits of shape J on K, then K ⋙ F preserves colimits after composing with G.
Русский
Если F создаёт колимиты и G сохраняет колимиты формы J на K, то K ⋙ F сохраняет колимиты после композиции с G.
LaTeX
$$$[\text{CreatesColimit } K F] \wedge [\text{PreservesColimit } K (F \circ G)] \Rightarrow \mathrm{PreservesColimit } (K \circ F) G$$$
Lean4
instance preservesColimit_comp_of_createsColimit [CreatesColimit K F] [PreservesColimit K (F ⋙ G)] :
PreservesColimit (K ⋙ F) G where
preserves
hc :=
⟨IsColimit.ofIsoColimit (isColimitOfPreserves (F ⋙ G) (liftedColimitIsColimit hc))
((Functor.mapCoconeMapCocone (liftColimit hc)).symm ≪≫
(Cocones.functoriality _ _).mapIso (liftedColimitMapsToOriginal hc))⟩