English
Under the localization L with a shift of M, HasSmallLocalizedShiftedHom W M X Y is equivalent to a family of small morphisms parameterized by M: all Hom spaces are small.
Русский
При локализации L с сдвигом M свойство HasSmallLocalizedShiftedHom эквивалентно семье малых морфизмов параметризованных по M: все пространства гомоморфизмов малые.
LaTeX
$$$ HasSmallLocalizedShiftedHom^{w} W M X Y \iff \forall a,b \in M, Small^w( (L.obj X)⟦a⟧ \to (L.obj Y)⟦b⟧) $$$
Lean4
theorem hasSmallLocalizedShiftedHom_iff (L : C ⥤ D) [L.IsLocalization W] [L.CommShift M] (X Y : C) :
HasSmallLocalizedShiftedHom.{w} W M X Y ↔ ∀ (a b : M), Small.{w} ((L.obj X)⟦a⟧ ⟶ (L.obj Y)⟦b⟧) :=
by
dsimp [HasSmallLocalizedShiftedHom]
have eq := fun (a b : M) ↦ small_congr.{w} (Iso.homCongr ((L.commShiftIso a).app X) ((L.commShiftIso b).app Y))
dsimp at eq
simp only [hasSmallLocalizedHom_iff _ L, eq]