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map {F G : J ⥤ C} (s : cone F) {t : cone G} (P : is_limit t) (α : F ⟶ G) : s.X ⟶ t.X
P.lift ((cones.postcompose α).obj s)
def
category_theory.limits.is_limit.map
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Given a natural transformation `α : F ⟶ G`, we give a morphism from the cone point of any cone over `F` to the cone point of a limit cone over `G`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_π {F G : J ⥤ C} (c : cone F) {d : cone G} (hd : is_limit d) (α : F ⟶ G) (j : J) : hd.map c α ≫ d.π.app j = c.π.app j ≫ α.app j
fac _ _ _
lemma
category_theory.limits.is_limit.map_π
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_self {c : cone F} (t : is_limit c) : t.lift c = 𝟙 c.X
(t.uniq _ _ (λ j, id_comp _)).symm
lemma
category_theory.limits.is_limit.lift_self
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_cone_morphism {t : cone F} (h : is_limit t) (s : cone F) : s ⟶ t
{ hom := h.lift s }
def
category_theory.limits.is_limit.lift_cone_morphism
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
The universal morphism from any other cone to a limit cone.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniq_cone_morphism {s t : cone F} (h : is_limit t) {f f' : s ⟶ t} : f = f'
have ∀ {g : s ⟶ t}, g = h.lift_cone_morphism s, by intro g; ext; exact h.uniq _ _ g.w, this.trans this.symm
lemma
category_theory.limits.is_limit.uniq_cone_morphism
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_unique {t : cone F} (h : is_limit t) (s : cone F) : ∃! (l : s.X ⟶ t.X), ∀ j, l ≫ t.π.app j = s.π.app j
⟨h.lift s, h.fac s, h.uniq s⟩
lemma
category_theory.limits.is_limit.exists_unique
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Restating the definition of a limit cone in terms of the ∃! operator.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_exists_unique {t : cone F} (ht : ∀ s : cone F, ∃! l : s.X ⟶ t.X, ∀ j, l ≫ t.π.app j = s.π.app j) : is_limit t
by { choose s hs hs' using ht, exact ⟨s, hs, hs'⟩ }
def
category_theory.limits.is_limit.of_exists_unique
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Noncomputably make a colimit cocone from the existence of unique factorizations.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_cone_morphism {t : cone F} (lift : Π (s : cone F), s ⟶ t) (uniq' : ∀ (s : cone F) (m : s ⟶ t), m = lift s) : is_limit t
{ lift := λ s, (lift s).hom, uniq' := λ s m w, have cone_morphism.mk m w = lift s, by apply uniq', congr_arg cone_morphism.hom this }
def
category_theory.limits.is_limit.mk_cone_morphism
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[ "lift" ]
Alternative constructor for `is_limit`, providing a morphism of cones rather than a morphism between the cone points and separately the factorisation condition.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unique_up_to_iso {s t : cone F} (P : is_limit s) (Q : is_limit t) : s ≅ t
{ hom := Q.lift_cone_morphism s, inv := P.lift_cone_morphism t, hom_inv_id' := P.uniq_cone_morphism, inv_hom_id' := Q.uniq_cone_morphism }
def
category_theory.limits.is_limit.unique_up_to_iso
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Limit cones on `F` are unique up to isomorphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_is_iso {s t : cone F} (P : is_limit s) (Q : is_limit t) (f : s ⟶ t) : is_iso f
⟨⟨P.lift_cone_morphism t, ⟨P.uniq_cone_morphism, Q.uniq_cone_morphism⟩⟩⟩
lemma
category_theory.limits.is_limit.hom_is_iso
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Any cone morphism between limit cones is an isomorphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cone_point_unique_up_to_iso {s t : cone F} (P : is_limit s) (Q : is_limit t) : s.X ≅ t.X
(cones.forget F).map_iso (unique_up_to_iso P Q)
def
category_theory.limits.is_limit.cone_point_unique_up_to_iso
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Limits of `F` are unique up to isomorphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cone_point_unique_up_to_iso_hom_comp {s t : cone F} (P : is_limit s) (Q : is_limit t) (j : J) : (cone_point_unique_up_to_iso P Q).hom ≫ t.π.app j = s.π.app j
(unique_up_to_iso P Q).hom.w _
lemma
category_theory.limits.is_limit.cone_point_unique_up_to_iso_hom_comp
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cone_point_unique_up_to_iso_inv_comp {s t : cone F} (P : is_limit s) (Q : is_limit t) (j : J) : (cone_point_unique_up_to_iso P Q).inv ≫ s.π.app j = t.π.app j
(unique_up_to_iso P Q).inv.w _
lemma
category_theory.limits.is_limit.cone_point_unique_up_to_iso_inv_comp
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_comp_cone_point_unique_up_to_iso_hom {r s t : cone F} (P : is_limit s) (Q : is_limit t) : P.lift r ≫ (cone_point_unique_up_to_iso P Q).hom = Q.lift r
Q.uniq _ _ (by simp)
lemma
category_theory.limits.is_limit.lift_comp_cone_point_unique_up_to_iso_hom
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_comp_cone_point_unique_up_to_iso_inv {r s t : cone F} (P : is_limit s) (Q : is_limit t) : Q.lift r ≫ (cone_point_unique_up_to_iso P Q).inv = P.lift r
P.uniq _ _ (by simp)
lemma
category_theory.limits.is_limit.lift_comp_cone_point_unique_up_to_iso_inv
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_iso_limit {r t : cone F} (P : is_limit r) (i : r ≅ t) : is_limit t
is_limit.mk_cone_morphism (λ s, P.lift_cone_morphism s ≫ i.hom) (λ s m, by rw ←i.comp_inv_eq; apply P.uniq_cone_morphism)
def
category_theory.limits.is_limit.of_iso_limit
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Transport evidence that a cone is a limit cone across an isomorphism of cones.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_iso_limit_lift {r t : cone F} (P : is_limit r) (i : r ≅ t) (s) : (P.of_iso_limit i).lift s = P.lift s ≫ i.hom.hom
rfl
lemma
category_theory.limits.is_limit.of_iso_limit_lift
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[ "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equiv_iso_limit {r t : cone F} (i : r ≅ t) : is_limit r ≃ is_limit t
{ to_fun := λ h, h.of_iso_limit i, inv_fun := λ h, h.of_iso_limit i.symm, left_inv := by tidy, right_inv := by tidy }
def
category_theory.limits.is_limit.equiv_iso_limit
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[ "inv_fun" ]
Isomorphism of cones preserves whether or not they are limiting cones.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equiv_iso_limit_apply {r t : cone F} (i : r ≅ t) (P : is_limit r) : equiv_iso_limit i P = P.of_iso_limit i
rfl
lemma
category_theory.limits.is_limit.equiv_iso_limit_apply
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equiv_iso_limit_symm_apply {r t : cone F} (i : r ≅ t) (P : is_limit t) : (equiv_iso_limit i).symm P = P.of_iso_limit i.symm
rfl
lemma
category_theory.limits.is_limit.equiv_iso_limit_symm_apply
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_point_iso {r t : cone F} (P : is_limit r) [i : is_iso (P.lift t)] : is_limit t
of_iso_limit P begin haveI : is_iso (P.lift_cone_morphism t).hom := i, haveI : is_iso (P.lift_cone_morphism t) := cones.cone_iso_of_hom_iso _, symmetry, apply as_iso (P.lift_cone_morphism t), end
def
category_theory.limits.is_limit.of_point_iso
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
If the canonical morphism from a cone point to a limiting cone point is an iso, then the first cone was limiting also.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_lift (h : is_limit t) {W : C} (m : W ⟶ t.X) : m = h.lift { X := W, π := { app := λ b, m ≫ t.π.app b } }
h.uniq { X := W, π := { app := λ b, m ≫ t.π.app b } } m (λ b, rfl)
lemma
category_theory.limits.is_limit.hom_lift
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_ext (h : is_limit t) {W : C} {f f' : W ⟶ t.X} (w : ∀ j, f ≫ t.π.app j = f' ≫ t.π.app j) : f = f'
by rw [h.hom_lift f, h.hom_lift f']; congr; exact funext w
lemma
category_theory.limits.is_limit.hom_ext
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[ "hom_ext" ]
Two morphisms into a limit are equal if their compositions with each cone morphism are equal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_right_adjoint {D : Type u₄} [category.{v₄} D] {G : K ⥤ D} (h : cone G ⥤ cone F) [is_right_adjoint h] {c : cone G} (t : is_limit c) : is_limit (h.obj c)
mk_cone_morphism (λ s, (adjunction.of_right_adjoint h).hom_equiv s c (t.lift_cone_morphism _)) (λ s m, (adjunction.eq_hom_equiv_apply _ _ _).2 t.uniq_cone_morphism)
def
category_theory.limits.is_limit.of_right_adjoint
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Given a right adjoint functor between categories of cones, the image of a limit cone is a limit cone.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_cone_equiv {D : Type u₄} [category.{v₄} D] {G : K ⥤ D} (h : cone G ≌ cone F) {c : cone G} : is_limit (h.functor.obj c) ≃ is_limit c
{ to_fun := λ P, of_iso_limit (of_right_adjoint h.inverse P) (h.unit_iso.symm.app c), inv_fun := of_right_adjoint h.functor, left_inv := by tidy, right_inv := by tidy, }
def
category_theory.limits.is_limit.of_cone_equiv
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[ "inv_fun" ]
Given two functors which have equivalent categories of cones, we can transport a limiting cone across the equivalence.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_cone_equiv_apply_desc {D : Type u₄} [category.{v₄} D] {G : K ⥤ D} (h : cone G ≌ cone F) {c : cone G} (P : is_limit (h.functor.obj c)) (s) : (of_cone_equiv h P).lift s = ((h.unit_iso.hom.app s).hom ≫ (h.functor.inv.map (P.lift_cone_morphism (h.functor.obj s))).hom) ≫ (h.unit_iso.inv.app c).hom
rfl
lemma
category_theory.limits.is_limit.of_cone_equiv_apply_desc
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[ "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_cone_equiv_symm_apply_desc {D : Type u₄} [category.{v₄} D] {G : K ⥤ D} (h : cone G ≌ cone F) {c : cone G} (P : is_limit c) (s) : ((of_cone_equiv h).symm P).lift s = (h.counit_iso.inv.app s).hom ≫ (h.functor.map (P.lift_cone_morphism (h.inverse.obj s))).hom
rfl
lemma
category_theory.limits.is_limit.of_cone_equiv_symm_apply_desc
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[ "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
postcompose_hom_equiv {F G : J ⥤ C} (α : F ≅ G) (c : cone F) : is_limit ((cones.postcompose α.hom).obj c) ≃ is_limit c
of_cone_equiv (cones.postcompose_equivalence α)
def
category_theory.limits.is_limit.postcompose_hom_equiv
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
A cone postcomposed with a natural isomorphism is a limit cone if and only if the original cone is.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
postcompose_inv_equiv {F G : J ⥤ C} (α : F ≅ G) (c : cone G) : is_limit ((cones.postcompose α.inv).obj c) ≃ is_limit c
postcompose_hom_equiv α.symm c
def
category_theory.limits.is_limit.postcompose_inv_equiv
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
A cone postcomposed with the inverse of a natural isomorphism is a limit cone if and only if the original cone is.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equiv_of_nat_iso_of_iso {F G : J ⥤ C} (α : F ≅ G) (c : cone F) (d : cone G) (w : (cones.postcompose α.hom).obj c ≅ d) : is_limit c ≃ is_limit d
(postcompose_hom_equiv α _).symm.trans (equiv_iso_limit w)
def
category_theory.limits.is_limit.equiv_of_nat_iso_of_iso
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Constructing an equivalence `is_limit c ≃ is_limit d` from a natural isomorphism between the underlying functors, and then an isomorphism between `c` transported along this and `d`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cone_points_iso_of_nat_iso {F G : J ⥤ C} {s : cone F} {t : cone G} (P : is_limit s) (Q : is_limit t) (w : F ≅ G) : s.X ≅ t.X
{ hom := Q.map s w.hom, inv := P.map t w.inv, hom_inv_id' := P.hom_ext (by tidy), inv_hom_id' := Q.hom_ext (by tidy), }
def
category_theory.limits.is_limit.cone_points_iso_of_nat_iso
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
The cone points of two limit cones for naturally isomorphic functors are themselves isomorphic.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cone_points_iso_of_nat_iso_hom_comp {F G : J ⥤ C} {s : cone F} {t : cone G} (P : is_limit s) (Q : is_limit t) (w : F ≅ G) (j : J) : (cone_points_iso_of_nat_iso P Q w).hom ≫ t.π.app j = s.π.app j ≫ w.hom.app j
by simp
lemma
category_theory.limits.is_limit.cone_points_iso_of_nat_iso_hom_comp
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cone_points_iso_of_nat_iso_inv_comp {F G : J ⥤ C} {s : cone F} {t : cone G} (P : is_limit s) (Q : is_limit t) (w : F ≅ G) (j : J) : (cone_points_iso_of_nat_iso P Q w).inv ≫ s.π.app j = t.π.app j ≫ w.inv.app j
by simp
lemma
category_theory.limits.is_limit.cone_points_iso_of_nat_iso_inv_comp
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_comp_cone_points_iso_of_nat_iso_hom {F G : J ⥤ C} {r s : cone F} {t : cone G} (P : is_limit s) (Q : is_limit t) (w : F ≅ G) : P.lift r ≫ (cone_points_iso_of_nat_iso P Q w).hom = Q.map r w.hom
Q.hom_ext (by simp)
lemma
category_theory.limits.is_limit.lift_comp_cone_points_iso_of_nat_iso_hom
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_comp_cone_points_iso_of_nat_iso_inv {F G : J ⥤ C} {r s : cone G} {t : cone F} (P : is_limit t) (Q : is_limit s) (w : F ≅ G) : Q.lift r ≫ (cone_points_iso_of_nat_iso P Q w).inv = P.map r w.inv
P.hom_ext (by simp)
lemma
category_theory.limits.is_limit.lift_comp_cone_points_iso_of_nat_iso_inv
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
whisker_equivalence {s : cone F} (P : is_limit s) (e : K ≌ J) : is_limit (s.whisker e.functor)
of_right_adjoint (cones.whiskering_equivalence e).functor P
def
category_theory.limits.is_limit.whisker_equivalence
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
If `s : cone F` is a limit cone, so is `s` whiskered by an equivalence `e`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_whisker_equivalence {s : cone F} (e : K ≌ J) (P : is_limit (s.whisker e.functor)) : is_limit s
equiv_iso_limit ((cones.whiskering_equivalence e).unit_iso.app s).symm (of_right_adjoint (cones.whiskering_equivalence e).inverse P : _)
def
category_theory.limits.is_limit.of_whisker_equivalence
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
If `s : cone F` whiskered by an equivalence `e` is a limit cone, so is `s`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
whisker_equivalence_equiv {s : cone F} (e : K ≌ J) : is_limit s ≃ is_limit (s.whisker e.functor)
⟨λ h, h.whisker_equivalence e, of_whisker_equivalence e, by tidy, by tidy⟩
def
category_theory.limits.is_limit.whisker_equivalence_equiv
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Given an equivalence of diagrams `e`, `s` is a limit cone iff `s.whisker e.functor` is.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cone_points_iso_of_equivalence {F : J ⥤ C} {s : cone F} {G : K ⥤ C} {t : cone G} (P : is_limit s) (Q : is_limit t) (e : J ≌ K) (w : e.functor ⋙ G ≅ F) : s.X ≅ t.X
let w' : e.inverse ⋙ F ≅ G := (iso_whisker_left e.inverse w).symm ≪≫ inv_fun_id_assoc e G in { hom := Q.lift ((cones.equivalence_of_reindexing e.symm w').functor.obj s), inv := P.lift ((cones.equivalence_of_reindexing e w).functor.obj t), hom_inv_id' := begin apply hom_ext P, intros j, dsimp, simp onl...
def
category_theory.limits.is_limit.cone_points_iso_of_equivalence
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[ "hom_ext" ]
We can prove two cone points `(s : cone F).X` and `(t.cone G).X` are isomorphic if * both cones are limit cones * their indexing categories are equivalent via some `e : J ≌ K`, * the triangle of functors commutes up to a natural isomorphism: `e.functor ⋙ G ≅ F`. This is the most general form of uniqueness of cone poin...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_iso (h : is_limit t) (W : C) : ulift.{u₁} (W ⟶ t.X : Type v₃) ≅ (const J).obj W ⟶ F
{ hom := λ f, (t.extend f.down).π, inv := λ π, ⟨h.lift { X := W, π := π }⟩, hom_inv_id' := by ext f; apply h.hom_ext; intro j; simp; dsimp; refl }
def
category_theory.limits.is_limit.hom_iso
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
The universal property of a limit cone: a map `W ⟶ X` is the same as a cone on `F` with vertex `W`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_iso_hom (h : is_limit t) {W : C} (f : ulift.{u₁} (W ⟶ t.X)) : (is_limit.hom_iso h W).hom f = (t.extend f.down).π
rfl
lemma
category_theory.limits.is_limit.hom_iso_hom
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_iso (h : is_limit t) : yoneda.obj t.X ⋙ ulift_functor.{u₁} ≅ F.cones
nat_iso.of_components (λ W, is_limit.hom_iso h (unop W)) (by tidy).
def
category_theory.limits.is_limit.nat_iso
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
The limit of `F` represents the functor taking `W` to the set of cones on `F` with vertex `W`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_iso' (h : is_limit t) (W : C) : ulift.{u₁} ((W ⟶ t.X) : Type v₃) ≅ { p : Π j, W ⟶ F.obj j // ∀ {j j'} (f : j ⟶ j'), p j ≫ F.map f = p j' }
h.hom_iso W ≪≫ { hom := λ π, ⟨λ j, π.app j, λ j j' f, by convert ←(π.naturality f).symm; apply id_comp⟩, inv := λ p, { app := λ j, p.1 j, naturality' := λ j j' f, begin dsimp, rw [id_comp], exact (p.2 f).symm end } }
def
category_theory.limits.is_limit.hom_iso'
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Another, more explicit, formulation of the universal property of a limit cone. See also `hom_iso`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_faithful {t : cone F} {D : Type u₄} [category.{v₄} D] (G : C ⥤ D) [faithful G] (ht : is_limit (G.map_cone t)) (lift : Π (s : cone F), s.X ⟶ t.X) (h : ∀ s, G.map (lift s) = ht.lift (G.map_cone s)) : is_limit t
{ lift := lift, fac' := λ s j, by apply G.map_injective; rw [G.map_comp, h]; apply ht.fac, uniq' := λ s m w, begin apply G.map_injective, rw h, refine ht.uniq (G.map_cone s) _ (λ j, _), convert ←congr_arg (λ f, G.map f) (w j), apply G.map_comp end }
def
category_theory.limits.is_limit.of_faithful
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[ "lift" ]
If G : C → D is a faithful functor which sends t to a limit cone, then it suffices to check that the induced maps for the image of t can be lifted to maps of C.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_cone_equiv {D : Type u₄} [category.{v₄} D] {K : J ⥤ C} {F G : C ⥤ D} (h : F ≅ G) {c : cone K} (t : is_limit (F.map_cone c)) : is_limit (G.map_cone c)
begin apply postcompose_inv_equiv (iso_whisker_left K h : _) (G.map_cone c) _, apply t.of_iso_limit (postcompose_whisker_left_map_cone h.symm c).symm, end
def
category_theory.limits.is_limit.map_cone_equiv
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
If `F` and `G` are naturally isomorphic, then `F.map_cone c` being a limit implies `G.map_cone c` is also a limit.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iso_unique_cone_morphism {t : cone F} : is_limit t ≅ Π s, unique (s ⟶ t)
{ hom := λ h s, { default := h.lift_cone_morphism s, uniq := λ _, h.uniq_cone_morphism }, inv := λ h, { lift := λ s, (h s).default.hom, uniq' := λ s f w, congr_arg cone_morphism.hom ((h s).uniq ⟨f, w⟩) } }
def
category_theory.limits.is_limit.iso_unique_cone_morphism
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[ "lift", "unique" ]
A cone is a limit cone exactly if there is a unique cone morphism from any other cone.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cone_of_hom {Y : C} (f : Y ⟶ X) : cone F
{ X := Y, π := h.hom.app (op Y) ⟨f⟩ }
def
category_theory.limits.is_limit.of_nat_iso.cone_of_hom
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
If `F.cones` is represented by `X`, each morphism `f : Y ⟶ X` gives a cone with cone point `Y`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_of_cone (s : cone F) : s.X ⟶ X
(h.inv.app (op s.X) s.π).down
def
category_theory.limits.is_limit.of_nat_iso.hom_of_cone
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
If `F.cones` is represented by `X`, each cone `s` gives a morphism `s.X ⟶ X`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cone_of_hom_of_cone (s : cone F) : cone_of_hom h (hom_of_cone h s) = s
begin dsimp [cone_of_hom, hom_of_cone], cases s, congr, dsimp, convert congr_fun (congr_fun (congr_arg nat_trans.app h.inv_hom_id) (op s_X)) s_π, exact ulift.up_down _ end
lemma
category_theory.limits.is_limit.of_nat_iso.cone_of_hom_of_cone
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_of_cone_of_hom {Y : C} (f : Y ⟶ X) : hom_of_cone h (cone_of_hom h f) = f
congr_arg ulift.down (congr_fun (congr_fun (congr_arg nat_trans.app h.hom_inv_id) (op Y)) ⟨f⟩ : _)
lemma
category_theory.limits.is_limit.of_nat_iso.hom_of_cone_of_hom
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
limit_cone : cone F
cone_of_hom h (𝟙 X)
def
category_theory.limits.is_limit.of_nat_iso.limit_cone
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
If `F.cones` is represented by `X`, the cone corresponding to the identity morphism on `X` will be a limit cone.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cone_of_hom_fac {Y : C} (f : Y ⟶ X) : cone_of_hom h f = (limit_cone h).extend f
begin dsimp [cone_of_hom, limit_cone, cone.extend], congr' with j, have t := congr_fun (h.hom.naturality f.op) ⟨𝟙 X⟩, dsimp at t, simp only [comp_id] at t, rw congr_fun (congr_arg nat_trans.app t) j, refl, end
lemma
category_theory.limits.is_limit.of_nat_iso.cone_of_hom_fac
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[ "extend" ]
If `F.cones` is represented by `X`, the cone corresponding to a morphism `f : Y ⟶ X` is the limit cone extended by `f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cone_fac (s : cone F) : (limit_cone h).extend (hom_of_cone h s) = s
begin rw ←cone_of_hom_of_cone h s, conv_lhs { simp only [hom_of_cone_of_hom] }, apply (cone_of_hom_fac _ _).symm, end
lemma
category_theory.limits.is_limit.of_nat_iso.cone_fac
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[ "extend" ]
If `F.cones` is represented by `X`, any cone is the extension of the limit cone by the corresponding morphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_nat_iso {X : C} (h : yoneda.obj X ⋙ ulift_functor.{u₁} ≅ F.cones) : is_limit (limit_cone h)
{ lift := λ s, hom_of_cone h s, fac' := λ s j, begin have h := cone_fac h s, cases s, injection h with h₁ h₂, simp only [heq_iff_eq] at h₂, conv_rhs { rw ← h₂ }, refl, end, uniq' := λ s m w, begin rw ←hom_of_cone_of_hom h m, congr, rw cone_of_hom_fac, dsimp [cone.extend], c...
def
category_theory.limits.is_limit.of_nat_iso
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[ "heq_iff_eq", "lift" ]
If `F.cones` is representable, then the cone corresponding to the identity morphism on the representing object is a limit cone.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_colimit (t : cocone F)
(desc : Π (s : cocone F), t.X ⟶ s.X) (fac' : ∀ (s : cocone F) (j : J), t.ι.app j ≫ desc s = s.ι.app j . obviously) (uniq' : ∀ (s : cocone F) (m : t.X ⟶ s.X) (w : ∀ j : J, t.ι.app j ≫ m = s.ι.app j), m = desc s . obviously)
structure
category_theory.limits.is_colimit
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
A cocone `t` on `F` is a colimit cocone if each cocone on `F` admits a unique cocone morphism from `t`. See <https://stacks.math.columbia.edu/tag/002F>.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
subsingleton {t : cocone F} : subsingleton (is_colimit t)
⟨by intros P Q; cases P; cases Q; congr; ext; solve_by_elim⟩
instance
category_theory.limits.is_colimit.subsingleton
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map {F G : J ⥤ C} {s : cocone F} (P : is_colimit s) (t : cocone G) (α : F ⟶ G) : s.X ⟶ t.X
P.desc ((cocones.precompose α).obj t)
def
category_theory.limits.is_colimit.map
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Given a natural transformation `α : F ⟶ G`, we give a morphism from the cocone point of a colimit cocone over `F` to the cocone point of any cocone over `G`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ι_map {F G : J ⥤ C} {c : cocone F} (hc : is_colimit c) (d : cocone G) (α : F ⟶ G) (j : J) : c.ι.app j ≫ is_colimit.map hc d α = α.app j ≫ d.ι.app j
fac _ _ _
lemma
category_theory.limits.is_colimit.ι_map
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
desc_self {t : cocone F} (h : is_colimit t) : h.desc t = 𝟙 t.X
(h.uniq _ _ (λ j, comp_id _)).symm
lemma
category_theory.limits.is_colimit.desc_self
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
desc_cocone_morphism {t : cocone F} (h : is_colimit t) (s : cocone F) : t ⟶ s
{ hom := h.desc s }
def
category_theory.limits.is_colimit.desc_cocone_morphism
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
The universal morphism from a colimit cocone to any other cocone.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
uniq_cocone_morphism {s t : cocone F} (h : is_colimit t) {f f' : t ⟶ s} : f = f'
have ∀ {g : t ⟶ s}, g = h.desc_cocone_morphism s, by intro g; ext; exact h.uniq _ _ g.w, this.trans this.symm
lemma
category_theory.limits.is_colimit.uniq_cocone_morphism
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
exists_unique {t : cocone F} (h : is_colimit t) (s : cocone F) : ∃! (d : t.X ⟶ s.X), ∀ j, t.ι.app j ≫ d = s.ι.app j
⟨h.desc s, h.fac s, h.uniq s⟩
lemma
category_theory.limits.is_colimit.exists_unique
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Restating the definition of a colimit cocone in terms of the ∃! operator.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_exists_unique {t : cocone F} (ht : ∀ s : cocone F, ∃! d : t.X ⟶ s.X, ∀ j, t.ι.app j ≫ d = s.ι.app j) : is_colimit t
by { choose s hs hs' using ht, exact ⟨s, hs, hs'⟩ }
def
category_theory.limits.is_colimit.of_exists_unique
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Noncomputably make a colimit cocone from the existence of unique factorizations.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mk_cocone_morphism {t : cocone F} (desc : Π (s : cocone F), t ⟶ s) (uniq' : ∀ (s : cocone F) (m : t ⟶ s), m = desc s) : is_colimit t
{ desc := λ s, (desc s).hom, uniq' := λ s m w, have cocone_morphism.mk m w = desc s, by apply uniq', congr_arg cocone_morphism.hom this }
def
category_theory.limits.is_colimit.mk_cocone_morphism
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Alternative constructor for `is_colimit`, providing a morphism of cocones rather than a morphism between the cocone points and separately the factorisation condition.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unique_up_to_iso {s t : cocone F} (P : is_colimit s) (Q : is_colimit t) : s ≅ t
{ hom := P.desc_cocone_morphism t, inv := Q.desc_cocone_morphism s, hom_inv_id' := P.uniq_cocone_morphism, inv_hom_id' := Q.uniq_cocone_morphism }
def
category_theory.limits.is_colimit.unique_up_to_iso
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Colimit cocones on `F` are unique up to isomorphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_is_iso {s t : cocone F} (P : is_colimit s) (Q : is_colimit t) (f : s ⟶ t) : is_iso f
⟨⟨Q.desc_cocone_morphism s, ⟨P.uniq_cocone_morphism, Q.uniq_cocone_morphism⟩⟩⟩
lemma
category_theory.limits.is_colimit.hom_is_iso
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Any cocone morphism between colimit cocones is an isomorphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cocone_point_unique_up_to_iso {s t : cocone F} (P : is_colimit s) (Q : is_colimit t) : s.X ≅ t.X
(cocones.forget F).map_iso (unique_up_to_iso P Q)
def
category_theory.limits.is_colimit.cocone_point_unique_up_to_iso
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Colimits of `F` are unique up to isomorphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_cocone_point_unique_up_to_iso_hom {s t : cocone F} (P : is_colimit s) (Q : is_colimit t) (j : J) : s.ι.app j ≫ (cocone_point_unique_up_to_iso P Q).hom = t.ι.app j
(unique_up_to_iso P Q).hom.w _
lemma
category_theory.limits.is_colimit.comp_cocone_point_unique_up_to_iso_hom
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_cocone_point_unique_up_to_iso_inv {s t : cocone F} (P : is_colimit s) (Q : is_colimit t) (j : J) : t.ι.app j ≫ (cocone_point_unique_up_to_iso P Q).inv = s.ι.app j
(unique_up_to_iso P Q).inv.w _
lemma
category_theory.limits.is_colimit.comp_cocone_point_unique_up_to_iso_inv
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cocone_point_unique_up_to_iso_hom_desc {r s t : cocone F} (P : is_colimit s) (Q : is_colimit t) : (cocone_point_unique_up_to_iso P Q).hom ≫ Q.desc r = P.desc r
P.uniq _ _ (by simp)
lemma
category_theory.limits.is_colimit.cocone_point_unique_up_to_iso_hom_desc
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cocone_point_unique_up_to_iso_inv_desc {r s t : cocone F} (P : is_colimit s) (Q : is_colimit t) : (cocone_point_unique_up_to_iso P Q).inv ≫ P.desc r = Q.desc r
Q.uniq _ _ (by simp)
lemma
category_theory.limits.is_colimit.cocone_point_unique_up_to_iso_inv_desc
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_iso_colimit {r t : cocone F} (P : is_colimit r) (i : r ≅ t) : is_colimit t
is_colimit.mk_cocone_morphism (λ s, i.inv ≫ P.desc_cocone_morphism s) (λ s m, by rw i.eq_inv_comp; apply P.uniq_cocone_morphism)
def
category_theory.limits.is_colimit.of_iso_colimit
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Transport evidence that a cocone is a colimit cocone across an isomorphism of cocones.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_iso_colimit_desc {r t : cocone F} (P : is_colimit r) (i : r ≅ t) (s) : (P.of_iso_colimit i).desc s = i.inv.hom ≫ P.desc s
rfl
lemma
category_theory.limits.is_colimit.of_iso_colimit_desc
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equiv_iso_colimit {r t : cocone F} (i : r ≅ t) : is_colimit r ≃ is_colimit t
{ to_fun := λ h, h.of_iso_colimit i, inv_fun := λ h, h.of_iso_colimit i.symm, left_inv := by tidy, right_inv := by tidy }
def
category_theory.limits.is_colimit.equiv_iso_colimit
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[ "inv_fun" ]
Isomorphism of cocones preserves whether or not they are colimiting cocones.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equiv_iso_colimit_apply {r t : cocone F} (i : r ≅ t) (P : is_colimit r) : equiv_iso_colimit i P = P.of_iso_colimit i
rfl
lemma
category_theory.limits.is_colimit.equiv_iso_colimit_apply
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equiv_iso_colimit_symm_apply {r t : cocone F} (i : r ≅ t) (P : is_colimit t) : (equiv_iso_colimit i).symm P = P.of_iso_colimit i.symm
rfl
lemma
category_theory.limits.is_colimit.equiv_iso_colimit_symm_apply
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_point_iso {r t : cocone F} (P : is_colimit r) [i : is_iso (P.desc t)] : is_colimit t
of_iso_colimit P begin haveI : is_iso (P.desc_cocone_morphism t).hom := i, haveI : is_iso (P.desc_cocone_morphism t) := cocones.cocone_iso_of_hom_iso _, apply as_iso (P.desc_cocone_morphism t), end
def
category_theory.limits.is_colimit.of_point_iso
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
If the canonical morphism to a cocone point from a colimiting cocone point is an iso, then the first cocone was colimiting also.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_desc (h : is_colimit t) {W : C} (m : t.X ⟶ W) : m = h.desc { X := W, ι := { app := λ b, t.ι.app b ≫ m, naturality' := by intros; erw [←assoc, t.ι.naturality, comp_id, comp_id] } }
h.uniq { X := W, ι := { app := λ b, t.ι.app b ≫ m, naturality' := _ } } m (λ b, rfl)
lemma
category_theory.limits.is_colimit.hom_desc
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_ext (h : is_colimit t) {W : C} {f f' : t.X ⟶ W} (w : ∀ j, t.ι.app j ≫ f = t.ι.app j ≫ f') : f = f'
by rw [h.hom_desc f, h.hom_desc f']; congr; exact funext w
lemma
category_theory.limits.is_colimit.hom_ext
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[ "hom_ext" ]
Two morphisms out of a colimit are equal if their compositions with each cocone morphism are equal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_left_adjoint {D : Type u₄} [category.{v₄} D] {G : K ⥤ D} (h : cocone G ⥤ cocone F) [is_left_adjoint h] {c : cocone G} (t : is_colimit c) : is_colimit (h.obj c)
mk_cocone_morphism (λ s, ((adjunction.of_left_adjoint h).hom_equiv c s).symm (t.desc_cocone_morphism _)) (λ s m, (adjunction.hom_equiv_apply_eq _ _ _).1 t.uniq_cocone_morphism)
def
category_theory.limits.is_colimit.of_left_adjoint
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Given a left adjoint functor between categories of cocones, the image of a colimit cocone is a colimit cocone.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_cocone_equiv {D : Type u₄} [category.{v₄} D] {G : K ⥤ D} (h : cocone G ≌ cocone F) {c : cocone G} : is_colimit (h.functor.obj c) ≃ is_colimit c
{ to_fun := λ P, of_iso_colimit (of_left_adjoint h.inverse P) (h.unit_iso.symm.app c), inv_fun := of_left_adjoint h.functor, left_inv := by tidy, right_inv := by tidy, }
def
category_theory.limits.is_colimit.of_cocone_equiv
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[ "inv_fun" ]
Given two functors which have equivalent categories of cocones, we can transport a colimiting cocone across the equivalence.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_cocone_equiv_apply_desc {D : Type u₄} [category.{v₄} D] {G : K ⥤ D} (h : cocone G ≌ cocone F) {c : cocone G} (P : is_colimit (h.functor.obj c)) (s) : (of_cocone_equiv h P).desc s = (h.unit.app c).hom ≫ (h.inverse.map (P.desc_cocone_morphism (h.functor.obj s))).hom ≫ (h.unit_inv.app s).hom
rfl
lemma
category_theory.limits.is_colimit.of_cocone_equiv_apply_desc
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_cocone_equiv_symm_apply_desc {D : Type u₄} [category.{v₄} D] {G : K ⥤ D} (h : cocone G ≌ cocone F) {c : cocone G} (P : is_colimit c) (s) : ((of_cocone_equiv h).symm P).desc s = (h.functor.map (P.desc_cocone_morphism (h.inverse.obj s))).hom ≫ (h.counit.app s).hom
rfl
lemma
category_theory.limits.is_colimit.of_cocone_equiv_symm_apply_desc
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
precompose_hom_equiv {F G : J ⥤ C} (α : F ≅ G) (c : cocone G) : is_colimit ((cocones.precompose α.hom).obj c) ≃ is_colimit c
of_cocone_equiv (cocones.precompose_equivalence α)
def
category_theory.limits.is_colimit.precompose_hom_equiv
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
A cocone precomposed with a natural isomorphism is a colimit cocone if and only if the original cocone is.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
precompose_inv_equiv {F G : J ⥤ C} (α : F ≅ G) (c : cocone F) : is_colimit ((cocones.precompose α.inv).obj c) ≃ is_colimit c
precompose_hom_equiv α.symm c
def
category_theory.limits.is_colimit.precompose_inv_equiv
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
A cocone precomposed with the inverse of a natural isomorphism is a colimit cocone if and only if the original cocone is.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equiv_of_nat_iso_of_iso {F G : J ⥤ C} (α : F ≅ G) (c : cocone F) (d : cocone G) (w : (cocones.precompose α.inv).obj c ≅ d) : is_colimit c ≃ is_colimit d
(precompose_inv_equiv α _).symm.trans (equiv_iso_colimit w)
def
category_theory.limits.is_colimit.equiv_of_nat_iso_of_iso
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Constructing an equivalence `is_colimit c ≃ is_colimit d` from a natural isomorphism between the underlying functors, and then an isomorphism between `c` transported along this and `d`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cocone_points_iso_of_nat_iso {F G : J ⥤ C} {s : cocone F} {t : cocone G} (P : is_colimit s) (Q : is_colimit t) (w : F ≅ G) : s.X ≅ t.X
{ hom := P.map t w.hom, inv := Q.map s w.inv, hom_inv_id' := P.hom_ext (by tidy), inv_hom_id' := Q.hom_ext (by tidy) }
def
category_theory.limits.is_colimit.cocone_points_iso_of_nat_iso
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
The cocone points of two colimit cocones for naturally isomorphic functors are themselves isomorphic.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_cocone_points_iso_of_nat_iso_hom {F G : J ⥤ C} {s : cocone F} {t : cocone G} (P : is_colimit s) (Q : is_colimit t) (w : F ≅ G) (j : J) : s.ι.app j ≫ (cocone_points_iso_of_nat_iso P Q w).hom = w.hom.app j ≫ t.ι.app j
by simp
lemma
category_theory.limits.is_colimit.comp_cocone_points_iso_of_nat_iso_hom
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp_cocone_points_iso_of_nat_iso_inv {F G : J ⥤ C} {s : cocone F} {t : cocone G} (P : is_colimit s) (Q : is_colimit t) (w : F ≅ G) (j : J) : t.ι.app j ≫ (cocone_points_iso_of_nat_iso P Q w).inv = w.inv.app j ≫ s.ι.app j
by simp
lemma
category_theory.limits.is_colimit.comp_cocone_points_iso_of_nat_iso_inv
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cocone_points_iso_of_nat_iso_hom_desc {F G : J ⥤ C} {s : cocone F} {r t : cocone G} (P : is_colimit s) (Q : is_colimit t) (w : F ≅ G) : (cocone_points_iso_of_nat_iso P Q w).hom ≫ Q.desc r = P.map _ w.hom
P.hom_ext (by simp)
lemma
category_theory.limits.is_colimit.cocone_points_iso_of_nat_iso_hom_desc
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cocone_points_iso_of_nat_iso_inv_desc {F G : J ⥤ C} {s : cocone G} {r t : cocone F} (P : is_colimit t) (Q : is_colimit s) (w : F ≅ G) : (cocone_points_iso_of_nat_iso P Q w).inv ≫ P.desc r = Q.map _ w.inv
Q.hom_ext (by simp)
lemma
category_theory.limits.is_colimit.cocone_points_iso_of_nat_iso_inv_desc
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
whisker_equivalence {s : cocone F} (P : is_colimit s) (e : K ≌ J) : is_colimit (s.whisker e.functor)
of_left_adjoint (cocones.whiskering_equivalence e).functor P
def
category_theory.limits.is_colimit.whisker_equivalence
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
If `s : cocone F` is a colimit cocone, so is `s` whiskered by an equivalence `e`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_whisker_equivalence {s : cocone F} (e : K ≌ J) (P : is_colimit (s.whisker e.functor)) : is_colimit s
equiv_iso_colimit ((cocones.whiskering_equivalence e).unit_iso.app s).symm (of_left_adjoint (cocones.whiskering_equivalence e).inverse P : _)
def
category_theory.limits.is_colimit.of_whisker_equivalence
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
If `s : cocone F` whiskered by an equivalence `e` is a colimit cocone, so is `s`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
whisker_equivalence_equiv {s : cocone F} (e : K ≌ J) : is_colimit s ≃ is_colimit (s.whisker e.functor)
⟨λ h, h.whisker_equivalence e, of_whisker_equivalence e, by tidy, by tidy⟩
def
category_theory.limits.is_colimit.whisker_equivalence_equiv
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Given an equivalence of diagrams `e`, `s` is a colimit cocone iff `s.whisker e.functor` is.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cocone_points_iso_of_equivalence {F : J ⥤ C} {s : cocone F} {G : K ⥤ C} {t : cocone G} (P : is_colimit s) (Q : is_colimit t) (e : J ≌ K) (w : e.functor ⋙ G ≅ F) : s.X ≅ t.X
let w' : e.inverse ⋙ F ≅ G := (iso_whisker_left e.inverse w).symm ≪≫ inv_fun_id_assoc e G in { hom := P.desc ((cocones.equivalence_of_reindexing e w).functor.obj t), inv := Q.desc ((cocones.equivalence_of_reindexing e.symm w').functor.obj s), hom_inv_id' := begin apply hom_ext P, intros j, dsimp, simp...
def
category_theory.limits.is_colimit.cocone_points_iso_of_equivalence
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[ "hom_ext" ]
We can prove two cocone points `(s : cocone F).X` and `(t.cocone G).X` are isomorphic if * both cocones are colimit cocones * their indexing categories are equivalent via some `e : J ≌ K`, * the triangle of functors commutes up to a natural isomorphism: `e.functor ⋙ G ≅ F`. This is the most general form of uniqueness ...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_iso (h : is_colimit t) (W : C) : ulift.{u₁} (t.X ⟶ W : Type v₃) ≅ (F ⟶ (const J).obj W)
{ hom := λ f, (t.extend f.down).ι, inv := λ ι, ⟨h.desc { X := W, ι := ι }⟩, hom_inv_id' := by ext f; apply h.hom_ext; intro j; simp; dsimp; refl }
def
category_theory.limits.is_colimit.hom_iso
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
The universal property of a colimit cocone: a map `X ⟶ W` is the same as a cocone on `F` with vertex `W`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_iso_hom (h : is_colimit t) {W : C} (f : ulift (t.X ⟶ W)) : (is_colimit.hom_iso h W).hom f = (t.extend f.down).ι
rfl
lemma
category_theory.limits.is_colimit.hom_iso_hom
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
nat_iso (h : is_colimit t) : coyoneda.obj (op t.X) ⋙ ulift_functor.{u₁} ≅ F.cocones
nat_iso.of_components (is_colimit.hom_iso h) (by intros; ext; dsimp; rw ←assoc; refl)
def
category_theory.limits.is_colimit.nat_iso
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
The colimit of `F` represents the functor taking `W` to the set of cocones on `F` with vertex `W`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_iso' (h : is_colimit t) (W : C) : ulift.{u₁} ((t.X ⟶ W) : Type v₃) ≅ { p : Π j, F.obj j ⟶ W // ∀ {j j' : J} (f : j ⟶ j'), F.map f ≫ p j' = p j }
h.hom_iso W ≪≫ { hom := λ ι, ⟨λ j, ι.app j, λ j j' f, by convert ←(ι.naturality f); apply comp_id⟩, inv := λ p, { app := λ j, p.1 j, naturality' := λ j j' f, begin dsimp, rw [comp_id], exact (p.2 f) end } }
def
category_theory.limits.is_colimit.hom_iso'
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
Another, more explicit, formulation of the universal property of a colimit cocone. See also `hom_iso`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_faithful {t : cocone F} {D : Type u₄} [category.{v₄} D] (G : C ⥤ D) [faithful G] (ht : is_colimit (G.map_cocone t)) (desc : Π (s : cocone F), t.X ⟶ s.X) (h : ∀ s, G.map (desc s) = ht.desc (G.map_cocone s)) : is_colimit t
{ desc := desc, fac' := λ s j, by apply G.map_injective; rw [G.map_comp, h]; apply ht.fac, uniq' := λ s m w, begin apply G.map_injective, rw h, refine ht.uniq (G.map_cocone s) _ (λ j, _), convert ←congr_arg (λ f, G.map f) (w j), apply G.map_comp end }
def
category_theory.limits.is_colimit.of_faithful
category_theory.limits
src/category_theory/limits/is_limit.lean
[ "category_theory.adjunction.basic", "category_theory.limits.cones" ]
[]
If G : C → D is a faithful functor which sends t to a colimit cocone, then it suffices to check that the induced maps for the image of t can be lifted to maps of C.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83