English
A functor preserving larger filtered colimits also preserves filtered colimits for smaller sizes (universes).
Русский
Функтор, сохраняющий более крупные фильтрованные колимиты, также сохраняет фильтрованные колимиты для меньших размеров (вселенных).
LaTeX
$$$PreservesFilteredColimitsOfSize.{w, w'} F \\Rightarrow PreservesFilteredColimitsOfSize.{w, w'} F$$$
Lean4
/-- A functor preserving larger filtered colimits also preserves smaller filtered colimits. -/
theorem preservesFilteredColimitsOfSize_of_univLE (F : C ⥤ D) [UnivLE.{w, w'}] [UnivLE.{w₂, w₂'}]
[PreservesFilteredColimitsOfSize.{w', w₂'} F] : PreservesFilteredColimitsOfSize.{w, w₂} F where
preserves_filtered_colimits J _
_ := by
let e := ((ShrinkHoms.equivalence J).trans <| Shrink.equivalence _).symm
haveI := IsFiltered.of_equivalence e.symm
exact preservesColimitsOfShape_of_equiv e F