English
If F creates limits and G preserves limits of shape J on K, then K ⋙ F preserves limits after composition with G.
Русский
Если F создает пределы и G сохраняет пределы формы J на K, то K ⋙ F сохраняет пределы после композиции с G.
LaTeX
$$$[\text{CreatesLimit } K F] \wedge [\text{PreservesLimit } K (F \circ G)] \Rightarrow \mathrm{PreservesLimit } (K \circ F) G$$$
Lean4
instance preservesLimit_comp_of_createsLimit [CreatesLimit K F] [PreservesLimit K (F ⋙ G)] : PreservesLimit (K ⋙ F) G
where
preserves
hc :=
⟨IsLimit.ofIsoLimit (isLimitOfPreserves (F ⋙ G) (liftedLimitIsLimit hc))
((Functor.mapConeMapCone (liftLimit hc)).symm ≪≫
(Cones.functoriality _ _).mapIso (liftedLimitMapsToOriginal hc))⟩