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binary_coproduct_iso_inl_comp_hom (X Y : Type u) : limits.coprod.inl ≫ (binary_coproduct_iso X Y).hom = sum.inl
colimit.iso_colimit_cocone_ι_hom (binary_coproduct_colimit_cocone X Y) ⟨walking_pair.left⟩
lemma
category_theory.limits.types.binary_coproduct_iso_inl_comp_hom
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_coproduct_iso_inr_comp_hom (X Y : Type u) : limits.coprod.inr ≫ (binary_coproduct_iso X Y).hom = sum.inr
colimit.iso_colimit_cocone_ι_hom (binary_coproduct_colimit_cocone X Y) ⟨walking_pair.right⟩
lemma
category_theory.limits.types.binary_coproduct_iso_inr_comp_hom
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_coproduct_iso_inl_comp_inv (X Y : Type u) : ↾(sum.inl : X ⟶ X ⊕ Y) ≫ (binary_coproduct_iso X Y).inv = limits.coprod.inl
colimit.iso_colimit_cocone_ι_inv (binary_coproduct_colimit_cocone X Y) ⟨walking_pair.left⟩
lemma
category_theory.limits.types.binary_coproduct_iso_inl_comp_inv
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_coproduct_iso_inr_comp_inv (X Y : Type u) : ↾(sum.inr : Y ⟶ X ⊕ Y) ≫ (binary_coproduct_iso X Y).inv = limits.coprod.inr
colimit.iso_colimit_cocone_ι_inv (binary_coproduct_colimit_cocone X Y) ⟨walking_pair.right⟩
lemma
category_theory.limits.types.binary_coproduct_iso_inr_comp_inv
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_cofan_is_colimit_iff {X Y : Type u} (c : binary_cofan X Y) : nonempty (is_colimit c) ↔ injective c.inl ∧ injective c.inr ∧ is_compl (set.range c.inl) (set.range c.inr)
begin classical, split, { rintro ⟨h⟩, rw [← show _ = c.inl, from h.comp_cocone_point_unique_up_to_iso_inv (binary_coproduct_colimit X Y) ⟨walking_pair.left⟩, ← show _ = c.inr, from h.comp_cocone_point_unique_up_to_iso_inv (binary_coproduct_colimit X Y) ⟨walking_pair.right⟩], dsimp [binar...
lemma
category_theory.limits.types.binary_cofan_is_colimit_iff
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[ "dite_eq_right_iff", "eq_compl_iff_is_compl", "equiv.apply_of_injective_symm", "equiv.of_injective", "equiv.of_injective_symm_apply", "forall_exists_index", "is_compl", "or_not", "set.image_compl_eq", "set.range", "set.range_comp", "sum.inl_injective", "sum.inr_injective" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_coprod_of_mono {X Y : Type u} (f : X ⟶ Y) [mono f] : is_colimit (binary_cofan.mk f (subtype.val : (set.range f)ᶜ → Y))
nonempty.some $ (binary_cofan_is_colimit_iff _).mpr ⟨(mono_iff_injective f).mp infer_instance, subtype.val_injective, (eq_compl_iff_is_compl.mp $ subtype.range_val).symm⟩
def
category_theory.limits.types.is_coprod_of_mono
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[ "nonempty.some", "set.range", "subtype.range_val", "subtype.val_injective" ]
Any monomorphism in `Type` is an coproduct injection.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
product_limit_cone {J : Type u} (F : J → Type (max u v)) : limits.limit_cone (discrete.functor F)
{ cone := { X := Π j, F j, π := { app := λ j f, f j.as }, }, is_limit := { lift := λ s x j, s.π.app ⟨j⟩ x, uniq' := λ s m w, funext $ λ x, funext $ λ j, (congr_fun (w ⟨j⟩) x : _) } }
def
category_theory.limits.types.product_limit_cone
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[ "lift" ]
The category of types has `Π j, f j` as the product of a type family `f : J → Type`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
product_iso {J : Type u} (F : J → Type (max u v)) : ∏ F ≅ Π j, F j
limit.iso_limit_cone (product_limit_cone F)
def
category_theory.limits.types.product_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
The categorical product in `Type u` is the type theoretic product `Π j, F j`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
product_iso_hom_comp_eval {J : Type u} (F : J → Type (max u v)) (j : J) : (product_iso F).hom ≫ (λ f, f j) = pi.π F j
rfl
lemma
category_theory.limits.types.product_iso_hom_comp_eval
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
product_iso_inv_comp_π {J : Type u} (F : J → Type (max u v)) (j : J) : (product_iso F).inv ≫ pi.π F j = (λ f, f j)
limit.iso_limit_cone_inv_π (product_limit_cone F) ⟨j⟩
lemma
category_theory.limits.types.product_iso_inv_comp_π
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coproduct_colimit_cocone {J : Type u} (F : J → Type u) : limits.colimit_cocone (discrete.functor F)
{ cocone := { X := Σ j, F j, ι := { app := λ j x, ⟨j.as, x⟩ }, }, is_colimit := { desc := λ s x, s.ι.app ⟨x.1⟩ x.2, uniq' := λ s m w, begin ext ⟨j, x⟩, have := congr_fun (w ⟨j⟩) x, exact this, end }, }
def
category_theory.limits.types.coproduct_colimit_cocone
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
The category of types has `Σ j, f j` as the coproduct of a type family `f : J → Type`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coproduct_iso {J : Type u} (F : J → Type u) : ∐ F ≅ Σ j, F j
colimit.iso_colimit_cocone (coproduct_colimit_cocone F)
def
category_theory.limits.types.coproduct_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
The categorical coproduct in `Type u` is the type theoretic coproduct `Σ j, F j`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coproduct_iso_ι_comp_hom {J : Type u} (F : J → Type u) (j : J) : sigma.ι F j ≫ (coproduct_iso F).hom = (λ x : F j, (⟨j, x⟩ : Σ j, F j))
colimit.iso_colimit_cocone_ι_hom (coproduct_colimit_cocone F) ⟨j⟩
lemma
category_theory.limits.types.coproduct_iso_ι_comp_hom
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coproduct_iso_mk_comp_inv {J : Type u} (F : J → Type u) (j : J) : ↾(λ x : F j, (⟨j, x⟩ : Σ j, F j)) ≫ (coproduct_iso F).inv = sigma.ι F j
rfl
lemma
category_theory.limits.types.coproduct_iso_mk_comp_inv
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
type_equalizer_of_unique (t : ∀ (y : Y), g y = h y → ∃! (x : X), f x = y) : is_limit (fork.of_ι _ w)
fork.is_limit.mk' _ $ λ s, begin refine ⟨λ i, _, _, _⟩, { apply classical.some (t (s.ι i) _), apply congr_fun s.condition i }, { ext i, apply (classical.some_spec (t (s.ι i) _)).1 }, { intros m hm, ext i, apply (classical.some_spec (t (s.ι i) _)).2, apply congr_fun hm i }, end
def
category_theory.limits.types.type_equalizer_of_unique
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
Show the given fork in `Type u` is an equalizer given that any element in the "difference kernel" comes from `X`. The converse of `unique_of_type_equalizer`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
unique_of_type_equalizer (t : is_limit (fork.of_ι _ w)) (y : Y) (hy : g y = h y) : ∃! (x : X), f x = y
begin let y' : punit ⟶ Y := λ _, y, have hy' : y' ≫ g = y' ≫ h := funext (λ _, hy), refine ⟨(fork.is_limit.lift' t _ hy').1 ⟨⟩, congr_fun (fork.is_limit.lift' t y' _).2 ⟨⟩, _⟩, intros x' hx', suffices : (λ (_ : punit), x') = (fork.is_limit.lift' t y' hy').1, rw ← this, apply fork.is_limit.hom_ext t, e...
lemma
category_theory.limits.types.unique_of_type_equalizer
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
The converse of `type_equalizer_of_unique`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
type_equalizer_iff_unique : nonempty (is_limit (fork.of_ι _ w)) ↔ (∀ (y : Y), g y = h y → ∃! (x : X), f x = y)
⟨λ i, unique_of_type_equalizer _ _ (classical.choice i), λ k, ⟨type_equalizer_of_unique f w k⟩⟩
lemma
category_theory.limits.types.type_equalizer_iff_unique
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equalizer_limit : limits.limit_cone (parallel_pair g h)
{ cone := fork.of_ι (subtype.val : {x : Y // g x = h x} → Y) (funext subtype.prop), is_limit := fork.is_limit.mk' _ $ λ s, ⟨λ i, ⟨s.ι i, by apply congr_fun s.condition i⟩, rfl, λ m hm, funext $ λ x, subtype.ext (congr_fun hm x)⟩ }
def
category_theory.limits.types.equalizer_limit
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[ "subtype.ext", "subtype.prop" ]
Show that the subtype `{x : Y // g x = h x}` is an equalizer for the pair `(g,h)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equalizer_iso : equalizer g h ≅ {x : Y // g x = h x}
limit.iso_limit_cone equalizer_limit
def
category_theory.limits.types.equalizer_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
The categorical equalizer in `Type u` is `{x : Y // g x = h x}`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equalizer_iso_hom_comp_subtype : (equalizer_iso g h).hom ≫ subtype.val = equalizer.ι g h
rfl
lemma
category_theory.limits.types.equalizer_iso_hom_comp_subtype
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equalizer_iso_inv_comp_ι : (equalizer_iso g h).inv ≫ equalizer.ι g h = subtype.val
limit.iso_limit_cone_inv_π equalizer_limit walking_parallel_pair.zero
lemma
category_theory.limits.types.equalizer_iso_inv_comp_ι
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coequalizer_rel : Y → Y → Prop | rel (x : X) : coequalizer_rel (f x) (g x)
inductive
category_theory.limits.types.coequalizer_rel
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[ "rel" ]
(Implementation) The relation to be quotiented to obtain the coequalizer.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coequalizer_colimit : limits.colimit_cocone (parallel_pair f g)
{ cocone := cofork.of_π (quot.mk (coequalizer_rel f g)) (funext (λ x, quot.sound (coequalizer_rel.rel x))), is_colimit := cofork.is_colimit.mk' _ $ λ s, ⟨ quot.lift s.π (λ a b (h : coequalizer_rel f g a b), by { cases h, exact congr_fun s.condition h_1 }), rfl, λ m hm, funext $ λ x, quot.i...
def
category_theory.limits.types.coequalizer_colimit
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
Show that the quotient by the relation generated by `f(x) ~ g(x)` is a coequalizer for the pair `(f, g)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coequalizer_preimage_image_eq_of_preimage_eq (π : Y ⟶ Z) (e : f ≫ π = g ≫ π) (h : is_colimit (cofork.of_π π e)) (U : set Y) (H : f ⁻¹' U = g ⁻¹' U) : π ⁻¹' (π '' U) = U
begin have lem : ∀ x y, (coequalizer_rel f g x y) → (x ∈ U ↔ y ∈ U), { rintros _ _ ⟨x⟩, change x ∈ f ⁻¹' U ↔ x ∈ g ⁻¹' U, congr' 2 }, have eqv : _root_.equivalence (λ x y, x ∈ U ↔ y ∈ U) := by tidy, ext, split, { rw ← (show _ = π, from h.comp_cocone_point_unique_up_to_iso_inv (coequalizer_colimit f g)...
lemma
category_theory.limits.types.coequalizer_preimage_image_eq_of_preimage_eq
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[ "eqv_gen.mono" ]
If `π : Y ⟶ Z` is an equalizer for `(f, g)`, and `U ⊆ Y` such that `f ⁻¹' U = g ⁻¹' U`, then `π ⁻¹' (π '' U) = U`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coequalizer_iso : coequalizer f g ≅ _root_.quot (coequalizer_rel f g)
colimit.iso_colimit_cocone (coequalizer_colimit f g)
def
category_theory.limits.types.coequalizer_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
The categorical coequalizer in `Type u` is the quotient by `f g ~ g x`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coequalizer_iso_π_comp_hom : coequalizer.π f g ≫ (coequalizer_iso f g).hom = quot.mk (coequalizer_rel f g)
colimit.iso_colimit_cocone_ι_hom (coequalizer_colimit f g) walking_parallel_pair.one
lemma
category_theory.limits.types.coequalizer_iso_π_comp_hom
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coequalizer_iso_quot_comp_inv : ↾(quot.mk (coequalizer_rel f g)) ≫ (coequalizer_iso f g).inv = coequalizer.π f g
rfl
lemma
category_theory.limits.types.coequalizer_iso_quot_comp_inv
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_obj : Type u
{ p : X × Y // f p.1 = g p.2 }
abbreviation
category_theory.limits.types.pullback_obj
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
The usual explicit pullback in the category of types, as a subtype of the product. The full `limit_cone` data is bundled as `pullback_limit_cone f g`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_cone : limits.pullback_cone f g
pullback_cone.mk (λ p : pullback_obj f g, p.1.1) (λ p, p.1.2) (funext (λ p, p.2))
abbreviation
category_theory.limits.types.pullback_cone
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
The explicit pullback cone on `pullback_obj f g`. This is bundled with the `is_limit` data as `pullback_limit_cone f g`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_limit_cone (f : X ⟶ Z) (g : Y ⟶ Z) : limits.limit_cone (cospan f g)
{ cone := pullback_cone f g, is_limit := pullback_cone.is_limit_aux _ (λ s x, ⟨⟨s.fst x, s.snd x⟩, congr_fun s.condition x⟩) (by tidy) (by tidy) (λ s m w, funext $ λ x, subtype.ext $ prod.ext (congr_fun (w walking_cospan.left) x) (congr_fun (w walking_cospan.right) x)) }
def
category_theory.limits.types.pullback_limit_cone
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[ "prod.ext", "subtype.ext" ]
The explicit pullback in the category of types, bundled up as a `limit_cone` for given `f` and `g`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_cone_iso_pullback : limit.cone (cospan f g) ≅ pullback_cone f g
(limit.is_limit _).unique_up_to_iso (pullback_limit_cone f g).is_limit
def
category_theory.limits.types.pullback_cone_iso_pullback
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
The pullback cone given by the instance `has_pullbacks (Type u)` is isomorphic to the explicit pullback cone given by `pullback_limit_cone`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_iso_pullback : pullback f g ≅ pullback_obj f g
(cones.forget _).map_iso $ pullback_cone_iso_pullback f g
def
category_theory.limits.types.pullback_iso_pullback
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
The pullback given by the instance `has_pullbacks (Type u)` is isomorphic to the explicit pullback object given by `pullback_limit_obj`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_iso_pullback_hom_fst (p : pullback f g) : ((pullback_iso_pullback f g).hom p : X × Y).fst = (pullback.fst : _ ⟶ X) p
congr_fun ((pullback_cone_iso_pullback f g).hom.w left) p
lemma
category_theory.limits.types.pullback_iso_pullback_hom_fst
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_iso_pullback_hom_snd (p : pullback f g) : ((pullback_iso_pullback f g).hom p : X × Y).snd = (pullback.snd : _ ⟶ Y) p
congr_fun ((pullback_cone_iso_pullback f g).hom.w right) p
lemma
category_theory.limits.types.pullback_iso_pullback_hom_snd
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_iso_pullback_inv_fst : (pullback_iso_pullback f g).inv ≫ pullback.fst = (λ p, (p : X × Y).fst)
(pullback_cone_iso_pullback f g).inv.w left
lemma
category_theory.limits.types.pullback_iso_pullback_inv_fst
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_iso_pullback_inv_snd : (pullback_iso_pullback f g).inv ≫ pullback.snd = (λ p, (p : X × Y).snd)
(pullback_cone_iso_pullback f g).inv.w right
lemma
category_theory.limits.types.pullback_iso_pullback_inv_snd
category_theory.limits.shapes
src/category_theory/limits/shapes/types.lean
[ "category_theory.limits.types", "category_theory.limits.shapes.products", "category_theory.limits.shapes.binary_products", "category_theory.limits.shapes.terminal", "category_theory.concrete_category.basic", "tactic.elementwise" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_parallel_family (J : Type w) : Type w | zero : walking_parallel_family | one : walking_parallel_family
inductive
category_theory.limits.walking_parallel_family
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
The type of objects for the diagram indexing a wide (co)equalizer.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_parallel_family.hom (J : Type w) : walking_parallel_family J → walking_parallel_family J → Type w | id : Π X : walking_parallel_family.{w} J, walking_parallel_family.hom X X | line : Π (j : J), walking_parallel_family.hom zero one
inductive
category_theory.limits.walking_parallel_family.hom
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
The type family of morphisms for the diagram indexing a wide (co)equalizer.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_parallel_family.hom.comp : Π (X Y Z : walking_parallel_family J) (f : walking_parallel_family.hom J X Y) (g : walking_parallel_family.hom J Y Z), walking_parallel_family.hom J X Z
| _ _ _ (id _) h := h | _ _ _ (line j) (id one) := line j.
def
category_theory.limits.walking_parallel_family.hom.comp
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
Composition of morphisms in the indexing diagram for wide (co)equalizers.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_parallel_family.category : small_category (walking_parallel_family J)
{ hom := walking_parallel_family.hom J, id := walking_parallel_family.hom.id, comp := walking_parallel_family.hom.comp }
instance
category_theory.limits.walking_parallel_family.category
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_parallel_family.hom_id (X : walking_parallel_family J) : walking_parallel_family.hom.id X = 𝟙 X
rfl
lemma
category_theory.limits.walking_parallel_family.hom_id
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
parallel_family : walking_parallel_family J ⥤ C
{ obj := λ x, walking_parallel_family.cases_on x X Y, map := λ x y h, match x, y, h with | _, _, (id _) := 𝟙 _ | _, _, (line j) := f j end, map_comp' := begin rintro _ _ _ ⟨⟩ ⟨⟩; { unfold_aux, simp; refl }, end }
def
category_theory.limits.parallel_family
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
`parallel_family f` is the diagram in `C` consisting of the given family of morphisms, each with common domain and codomain.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
parallel_family_obj_zero : (parallel_family f).obj zero = X
rfl
lemma
category_theory.limits.parallel_family_obj_zero
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
parallel_family_obj_one : (parallel_family f).obj one = Y
rfl
lemma
category_theory.limits.parallel_family_obj_one
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
parallel_family_map_left {j : J} : (parallel_family f).map (line j) = f j
rfl
lemma
category_theory.limits.parallel_family_map_left
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diagram_iso_parallel_family (F : walking_parallel_family J ⥤ C) : F ≅ parallel_family (λ j, F.map (line j))
nat_iso.of_components (λ j, eq_to_iso $ by cases j; tidy) $ by tidy
def
category_theory.limits.diagram_iso_parallel_family
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
Every functor indexing a wide (co)equalizer is naturally isomorphic (actually, equal) to a `parallel_family`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_parallel_family_equiv_walking_parallel_pair : walking_parallel_family.{w} (ulift bool) ≌ walking_parallel_pair
{ functor := parallel_family (λ p, cond p.down walking_parallel_pair_hom.left walking_parallel_pair_hom.right), inverse := parallel_pair (line (ulift.up tt)) (line (ulift.up ff)), unit_iso := nat_iso.of_components (λ X, eq_to_iso (by cases X; refl)) (by tidy), counit_iso := nat_iso.of_components (λ X, eq_to...
def
category_theory.limits.walking_parallel_family_equiv_walking_parallel_pair
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
`walking_parallel_pair` as a category is equivalent to a special case of `walking_parallel_family`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trident
cone (parallel_family f)
abbreviation
category_theory.limits.trident
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
A trident on `f` is just a `cone (parallel_family f)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cotrident
cocone (parallel_family f)
abbreviation
category_theory.limits.cotrident
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
A cotrident on `f` and `g` is just a `cocone (parallel_family f)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trident.ι (t : trident f)
t.π.app zero
abbreviation
category_theory.limits.trident.ι
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
A trident `t` on the parallel family `f : J → (X ⟶ Y)` consists of two morphisms `t.π.app zero : t.X ⟶ X` and `t.π.app one : t.X ⟶ Y`. Of these, only the first one is interesting, and we give it the shorter name `trident.ι t`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cotrident.π (t : cotrident f)
t.ι.app one
abbreviation
category_theory.limits.cotrident.π
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
A cotrident `t` on the parallel family `f : J → (X ⟶ Y)` consists of two morphisms `t.ι.app zero : X ⟶ t.X` and `t.ι.app one : Y ⟶ t.X`. Of these, only the second one is interesting, and we give it the shorter name `cotrident.π t`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trident.ι_eq_app_zero (t : trident f) : t.ι = t.π.app zero
rfl
lemma
category_theory.limits.trident.ι_eq_app_zero
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cotrident.π_eq_app_one (t : cotrident f) : t.π = t.ι.app one
rfl
lemma
category_theory.limits.cotrident.π_eq_app_one
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trident.app_zero (s : trident f) (j : J) : s.π.app zero ≫ f j = s.π.app one
by rw [←s.w (line j), parallel_family_map_left]
lemma
category_theory.limits.trident.app_zero
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cotrident.app_one (s : cotrident f) (j : J) : f j ≫ s.ι.app one = s.ι.app zero
by rw [←s.w (line j), parallel_family_map_left]
lemma
category_theory.limits.cotrident.app_one
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trident.of_ι [nonempty J] {P : C} (ι : P ⟶ X) (w : ∀ j₁ j₂, ι ≫ f j₁ = ι ≫ f j₂) : trident f
{ X := P, π := { app := λ X, walking_parallel_family.cases_on X ι (ι ≫ f (classical.arbitrary J)), naturality' := λ i j f, begin dsimp, cases f with _ k, { simp }, { simp [w (classical.arbitrary J) k] }, end } }
def
category_theory.limits.trident.of_ι
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[ "classical.arbitrary" ]
A trident on `f : J → (X ⟶ Y)` is determined by the morphism `ι : P ⟶ X` satisfying `∀ j₁ j₂, ι ≫ f j₁ = ι ≫ f j₂`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cotrident.of_π [nonempty J] {P : C} (π : Y ⟶ P) (w : ∀ j₁ j₂, f j₁ ≫ π = f j₂ ≫ π) : cotrident f
{ X := P, ι := { app := λ X, walking_parallel_family.cases_on X (f (classical.arbitrary J) ≫ π) π, naturality' := λ i j f, begin dsimp, cases f with _ k, { simp }, { simp [w (classical.arbitrary J) k] } end } }
def
category_theory.limits.cotrident.of_π
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[ "classical.arbitrary" ]
A cotrident on `f : J → (X ⟶ Y)` is determined by the morphism `π : Y ⟶ P` satisfying `∀ j₁ j₂, f j₁ ≫ π = f j₂ ≫ π`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trident.ι_of_ι [nonempty J] {P : C} (ι : P ⟶ X) (w : ∀ j₁ j₂, ι ≫ f j₁ = ι ≫ f j₂) : (trident.of_ι ι w).ι = ι
rfl
lemma
category_theory.limits.trident.ι_of_ι
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cotrident.π_of_π [nonempty J] {P : C} (π : Y ⟶ P) (w : ∀ j₁ j₂, f j₁ ≫ π = f j₂ ≫ π) : (cotrident.of_π π w).π = π
rfl
lemma
category_theory.limits.cotrident.π_of_π
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trident.condition (j₁ j₂ : J) (t : trident f) : t.ι ≫ f j₁ = t.ι ≫ f j₂
by rw [t.app_zero, t.app_zero]
lemma
category_theory.limits.trident.condition
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cotrident.condition (j₁ j₂ : J) (t : cotrident f) : f j₁ ≫ t.π = f j₂ ≫ t.π
by rw [t.app_one, t.app_one]
lemma
category_theory.limits.cotrident.condition
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trident.equalizer_ext [nonempty J] (s : trident f) {W : C} {k l : W ⟶ s.X} (h : k ≫ s.ι = l ≫ s.ι) : ∀ (j : walking_parallel_family J), k ≫ s.π.app j = l ≫ s.π.app j
| zero := h | one := by rw [←s.app_zero (classical.arbitrary J), reassoc_of h]
lemma
category_theory.limits.trident.equalizer_ext
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[ "classical.arbitrary" ]
To check whether two maps are equalized by both maps of a trident, it suffices to check it for the first map
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cotrident.coequalizer_ext [nonempty J] (s : cotrident f) {W : C} {k l : s.X ⟶ W} (h : s.π ≫ k = s.π ≫ l) : ∀ (j : walking_parallel_family J), s.ι.app j ≫ k = s.ι.app j ≫ l
| zero := by rw [←s.app_one (classical.arbitrary J), category.assoc, category.assoc, h] | one := h
lemma
category_theory.limits.cotrident.coequalizer_ext
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[ "classical.arbitrary" ]
To check whether two maps are coequalized by both maps of a cotrident, it suffices to check it for the second map
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trident.is_limit.hom_ext [nonempty J] {s : trident f} (hs : is_limit s) {W : C} {k l : W ⟶ s.X} (h : k ≫ s.ι = l ≫ s.ι) : k = l
hs.hom_ext $ trident.equalizer_ext _ h
lemma
category_theory.limits.trident.is_limit.hom_ext
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cotrident.is_colimit.hom_ext [nonempty J] {s : cotrident f} (hs : is_colimit s) {W : C} {k l : s.X ⟶ W} (h : s.π ≫ k = s.π ≫ l) : k = l
hs.hom_ext $ cotrident.coequalizer_ext _ h
lemma
category_theory.limits.cotrident.is_colimit.hom_ext
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trident.is_limit.lift' [nonempty J] {s : trident f} (hs : is_limit s) {W : C} (k : W ⟶ X) (h : ∀ j₁ j₂, k ≫ f j₁ = k ≫ f j₂) : {l : W ⟶ s.X // l ≫ trident.ι s = k}
⟨hs.lift $ trident.of_ι _ h, hs.fac _ _⟩
def
category_theory.limits.trident.is_limit.lift'
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
If `s` is a limit trident over `f`, then a morphism `k : W ⟶ X` satisfying `∀ j₁ j₂, k ≫ f j₁ = k ≫ f j₂` induces a morphism `l : W ⟶ s.X` such that `l ≫ trident.ι s = k`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cotrident.is_colimit.desc' [nonempty J] {s : cotrident f} (hs : is_colimit s) {W : C} (k : Y ⟶ W) (h : ∀ j₁ j₂, f j₁ ≫ k = f j₂ ≫ k) : {l : s.X ⟶ W // cotrident.π s ≫ l = k}
⟨hs.desc $ cotrident.of_π _ h, hs.fac _ _⟩
def
category_theory.limits.cotrident.is_colimit.desc'
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
If `s` is a colimit cotrident over `f`, then a morphism `k : Y ⟶ W` satisfying `∀ j₁ j₂, f j₁ ≫ k = f j₂ ≫ k` induces a morphism `l : s.X ⟶ W` such that `cotrident.π s ≫ l = k`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trident.is_limit.mk [nonempty J] (t : trident f) (lift : Π (s : trident f), s.X ⟶ t.X) (fac : ∀ (s : trident f), lift s ≫ t.ι = s.ι) (uniq : ∀ (s : trident f) (m : s.X ⟶ t.X) (w : ∀ j : walking_parallel_family J, m ≫ t.π.app j = s.π.app j), m = lift s) : is_limit t
{ lift := lift, fac' := λ s j, walking_parallel_family.cases_on j (fac s) (by rw [←t.w (line (classical.arbitrary J)), reassoc_of fac, s.w]), uniq' := uniq }
def
category_theory.limits.trident.is_limit.mk
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[ "classical.arbitrary", "lift" ]
This is a slightly more convenient method to verify that a trident is a limit cone. It only asks for a proof of facts that carry any mathematical content
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trident.is_limit.mk' [nonempty J] (t : trident f) (create : Π (s : trident f), {l // l ≫ t.ι = s.ι ∧ ∀ {m}, m ≫ t.ι = s.ι → m = l}) : is_limit t
trident.is_limit.mk t (λ s, (create s).1) (λ s, (create s).2.1) (λ s m w, (create s).2.2 (w zero))
def
category_theory.limits.trident.is_limit.mk'
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
This is another convenient method to verify that a trident is a limit cone. It only asks for a proof of facts that carry any mathematical content, and allows access to the same `s` for all parts.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cotrident.is_colimit.mk [nonempty J] (t : cotrident f) (desc : Π (s : cotrident f), t.X ⟶ s.X) (fac : ∀ (s : cotrident f), t.π ≫ desc s = s.π) (uniq : ∀ (s : cotrident f) (m : t.X ⟶ s.X) (w : ∀ j : walking_parallel_family J, t.ι.app j ≫ m = s.ι.app j), m = desc s) : is_colimit t
{ desc := desc, fac' := λ s j, walking_parallel_family.cases_on j (by rw [←t.w_assoc (line (classical.arbitrary J)), fac, s.w]) (fac s), uniq' := uniq }
def
category_theory.limits.cotrident.is_colimit.mk
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[ "classical.arbitrary" ]
This is a slightly more convenient method to verify that a cotrident is a colimit cocone. It only asks for a proof of facts that carry any mathematical content
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cotrident.is_colimit.mk' [nonempty J] (t : cotrident f) (create : Π (s : cotrident f), {l : t.X ⟶ s.X // t.π ≫ l = s.π ∧ ∀ {m}, t.π ≫ m = s.π → m = l}) : is_colimit t
cotrident.is_colimit.mk t (λ s, (create s).1) (λ s, (create s).2.1) (λ s m w, (create s).2.2 (w one))
def
category_theory.limits.cotrident.is_colimit.mk'
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
This is another convenient method to verify that a cotrident is a colimit cocone. It only asks for a proof of facts that carry any mathematical content, and allows access to the same `s` for all parts.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trident.is_limit.hom_iso [nonempty J] {t : trident f} (ht : is_limit t) (Z : C) : (Z ⟶ t.X) ≃ {h : Z ⟶ X // ∀ j₁ j₂, h ≫ f j₁ = h ≫ f j₂}
{ to_fun := λ k, ⟨k ≫ t.ι, by simp⟩, inv_fun := λ h, (trident.is_limit.lift' ht _ h.prop).1, left_inv := λ k, trident.is_limit.hom_ext ht (trident.is_limit.lift' _ _ _).prop, right_inv := λ h, subtype.ext (trident.is_limit.lift' ht _ _).prop }
def
category_theory.limits.trident.is_limit.hom_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[ "inv_fun", "subtype.ext" ]
Given a limit cone for the family `f : J → (X ⟶ Y)`, for any `Z`, morphisms from `Z` to its point are in bijection with morphisms `h : Z ⟶ X` such that `∀ j₁ j₂, h ≫ f j₁ = h ≫ f j₂`. Further, this bijection is natural in `Z`: see `trident.is_limit.hom_iso_natural`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trident.is_limit.hom_iso_natural [nonempty J] {t : trident f} (ht : is_limit t) {Z Z' : C} (q : Z' ⟶ Z) (k : Z ⟶ t.X) : (trident.is_limit.hom_iso ht _ (q ≫ k) : Z' ⟶ X) = q ≫ (trident.is_limit.hom_iso ht _ k : Z ⟶ X)
category.assoc _ _ _
lemma
category_theory.limits.trident.is_limit.hom_iso_natural
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
The bijection of `trident.is_limit.hom_iso` is natural in `Z`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cotrident.is_colimit.hom_iso [nonempty J] {t : cotrident f} (ht : is_colimit t) (Z : C) : (t.X ⟶ Z) ≃ {h : Y ⟶ Z // ∀ j₁ j₂, f j₁ ≫ h = f j₂ ≫ h}
{ to_fun := λ k, ⟨t.π ≫ k, by simp⟩, inv_fun := λ h, (cotrident.is_colimit.desc' ht _ h.prop).1, left_inv := λ k, cotrident.is_colimit.hom_ext ht (cotrident.is_colimit.desc' _ _ _).prop, right_inv := λ h, subtype.ext (cotrident.is_colimit.desc' ht _ _).prop }
def
category_theory.limits.cotrident.is_colimit.hom_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[ "inv_fun", "subtype.ext" ]
Given a colimit cocone for the family `f : J → (X ⟶ Y)`, for any `Z`, morphisms from the cocone point to `Z` are in bijection with morphisms `h : Z ⟶ X` such that `∀ j₁ j₂, f j₁ ≫ h = f j₂ ≫ h`. Further, this bijection is natural in `Z`: see `cotrident.is_colimit.hom_iso_natural`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cotrident.is_colimit.hom_iso_natural [nonempty J] {t : cotrident f} {Z Z' : C} (q : Z ⟶ Z') (ht : is_colimit t) (k : t.X ⟶ Z) : (cotrident.is_colimit.hom_iso ht _ (k ≫ q) : Y ⟶ Z') = (cotrident.is_colimit.hom_iso ht _ k : Y ⟶ Z) ≫ q
(category.assoc _ _ _).symm
lemma
category_theory.limits.cotrident.is_colimit.hom_iso_natural
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
The bijection of `cotrident.is_colimit.hom_iso` is natural in `Z`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cone.of_trident {F : walking_parallel_family J ⥤ C} (t : trident (λ j, F.map (line j))) : cone F
{ X := t.X, π := { app := λ X, t.π.app X ≫ eq_to_hom (by tidy), naturality' := λ j j' g, by { cases g; { dsimp, simp } } } }
def
category_theory.limits.cone.of_trident
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
This is a helper construction that can be useful when verifying that a category has certain wide equalizers. Given `F : walking_parallel_family ⥤ C`, which is really the same as `parallel_family (λ j, F.map (line j))`, and a trident on `λ j, F.map (line j)`, we get a cone on `F`. If you're thinking abo...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cocone.of_cotrident {F : walking_parallel_family J ⥤ C} (t : cotrident (λ j, F.map (line j))) : cocone F
{ X := t.X, ι := { app := λ X, eq_to_hom (by tidy) ≫ t.ι.app X, naturality' := λ j j' g, by { cases g; dsimp; simp [cotrident.app_one t] } } }
def
category_theory.limits.cocone.of_cotrident
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
This is a helper construction that can be useful when verifying that a category has all coequalizers. Given `F : walking_parallel_family ⥤ C`, which is really the same as `parallel_family (λ j, F.map (line j))`, and a cotrident on `λ j, F.map (line j)` we get a cocone on `F`. If you're thinking about u...
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cone.of_trident_π {F : walking_parallel_family J ⥤ C} (t : trident (λ j, F.map (line j))) (j) : (cone.of_trident t).π.app j = t.π.app j ≫ eq_to_hom (by tidy)
rfl
lemma
category_theory.limits.cone.of_trident_π
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cocone.of_cotrident_ι {F : walking_parallel_family J ⥤ C} (t : cotrident (λ j, F.map (line j))) (j) : (cocone.of_cotrident t).ι.app j = eq_to_hom (by tidy) ≫ t.ι.app j
rfl
lemma
category_theory.limits.cocone.of_cotrident_ι
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trident.of_cone {F : walking_parallel_family J ⥤ C} (t : cone F) : trident (λ j, F.map (line j))
{ X := t.X, π := { app := λ X, t.π.app X ≫ eq_to_hom (by tidy) } }
def
category_theory.limits.trident.of_cone
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
Given `F : walking_parallel_family ⥤ C`, which is really the same as `parallel_family (λ j, F.map (line j))` and a cone on `F`, we get a trident on `λ j, F.map (line j)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cotrident.of_cocone {F : walking_parallel_family J ⥤ C} (t : cocone F) : cotrident (λ j, F.map (line j))
{ X := t.X, ι := { app := λ X, eq_to_hom (by tidy) ≫ t.ι.app X } }
def
category_theory.limits.cotrident.of_cocone
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
Given `F : walking_parallel_family ⥤ C`, which is really the same as `parallel_family (F.map left) (F.map right)` and a cocone on `F`, we get a cotrident on `λ j, F.map (line j)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trident.of_cone_π {F : walking_parallel_family J ⥤ C} (t : cone F) (j) : (trident.of_cone t).π.app j = t.π.app j ≫ eq_to_hom (by tidy)
rfl
lemma
category_theory.limits.trident.of_cone_π
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cotrident.of_cocone_ι {F : walking_parallel_family J ⥤ C} (t : cocone F) (j) : (cotrident.of_cocone t).ι.app j = eq_to_hom (by tidy) ≫ t.ι.app j
rfl
lemma
category_theory.limits.cotrident.of_cocone_ι
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trident.mk_hom [nonempty J] {s t : trident f} (k : s.X ⟶ t.X) (w : k ≫ t.ι = s.ι) : s ⟶ t
{ hom := k, w' := begin rintro ⟨_|_⟩, { exact w }, { simpa using w =≫ f (classical.arbitrary J) }, end }
def
category_theory.limits.trident.mk_hom
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[ "classical.arbitrary" ]
Helper function for constructing morphisms between wide equalizer tridents.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
trident.ext [nonempty J] {s t : trident f} (i : s.X ≅ t.X) (w : i.hom ≫ t.ι = s.ι) : s ≅ t
{ hom := trident.mk_hom i.hom w, inv := trident.mk_hom i.inv (by rw [← w, iso.inv_hom_id_assoc]) }
def
category_theory.limits.trident.ext
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
To construct an isomorphism between tridents, it suffices to give an isomorphism between the cone points and check that it commutes with the `ι` morphisms.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cotrident.mk_hom [nonempty J] {s t : cotrident f} (k : s.X ⟶ t.X) (w : s.π ≫ k = t.π) : s ⟶ t
{ hom := k, w' := begin rintro ⟨_|_⟩, { simpa using f (classical.arbitrary J) ≫= w }, { exact w }, end }
def
category_theory.limits.cotrident.mk_hom
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[ "classical.arbitrary" ]
Helper function for constructing morphisms between coequalizer cotridents.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
cotrident.ext [nonempty J] {s t : cotrident f} (i : s.X ≅ t.X) (w : s.π ≫ i.hom = t.π) : s ≅ t
{ hom := cotrident.mk_hom i.hom w, inv := cotrident.mk_hom i.inv (by rw [iso.comp_inv_eq, w]) }
def
category_theory.limits.cotrident.ext
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
To construct an isomorphism between cotridents, it suffices to give an isomorphism between the cocone points and check that it commutes with the `π` morphisms.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_wide_equalizer
has_limit (parallel_family f)
abbreviation
category_theory.limits.has_wide_equalizer
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
`has_wide_equalizer f` represents a particular choice of limiting cone for the parallel family of morphisms `f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
wide_equalizer : C
limit (parallel_family f)
abbreviation
category_theory.limits.wide_equalizer
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
If a wide equalizer of `f` exists, we can access an arbitrary choice of such by saying `wide_equalizer f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
wide_equalizer.ι : wide_equalizer f ⟶ X
limit.π (parallel_family f) zero
abbreviation
category_theory.limits.wide_equalizer.ι
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
If a wide equalizer of `f` exists, we can access the inclusion `wide_equalizer f ⟶ X` by saying `wide_equalizer.ι f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
wide_equalizer.trident : trident f
limit.cone (parallel_family f)
abbreviation
category_theory.limits.wide_equalizer.trident
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
A wide equalizer cone for a parallel family `f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
wide_equalizer.trident_ι : (wide_equalizer.trident f).ι = wide_equalizer.ι f
rfl
lemma
category_theory.limits.wide_equalizer.trident_ι
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
wide_equalizer.trident_π_app_zero : (wide_equalizer.trident f).π.app zero = wide_equalizer.ι f
rfl
lemma
category_theory.limits.wide_equalizer.trident_π_app_zero
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
wide_equalizer.condition (j₁ j₂ : J) : wide_equalizer.ι f ≫ f j₁ = wide_equalizer.ι f ≫ f j₂
trident.condition j₁ j₂ $ limit.cone $ parallel_family f
lemma
category_theory.limits.wide_equalizer.condition
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
wide_equalizer_is_wide_equalizer [nonempty J] : is_limit (trident.of_ι (wide_equalizer.ι f) (wide_equalizer.condition f))
is_limit.of_iso_limit (limit.is_limit _) (trident.ext (iso.refl _) (by tidy))
def
category_theory.limits.wide_equalizer_is_wide_equalizer
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
The wide_equalizer built from `wide_equalizer.ι f` is limiting.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
wide_equalizer.lift [nonempty J] {W : C} (k : W ⟶ X) (h : ∀ j₁ j₂, k ≫ f j₁ = k ≫ f j₂) : W ⟶ wide_equalizer f
limit.lift (parallel_family f) (trident.of_ι k h)
abbreviation
category_theory.limits.wide_equalizer.lift
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
A morphism `k : W ⟶ X` satisfying `∀ j₁ j₂, k ≫ f j₁ = k ≫ f j₂` factors through the wide equalizer of `f` via `wide_equalizer.lift : W ⟶ wide_equalizer f`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
wide_equalizer.lift_ι [nonempty J] {W : C} (k : W ⟶ X) (h : ∀ j₁ j₂, k ≫ f j₁ = k ≫ f j₂) : wide_equalizer.lift k h ≫ wide_equalizer.ι f = k
limit.lift_π _ _
lemma
category_theory.limits.wide_equalizer.lift_ι
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
wide_equalizer.lift' [nonempty J] {W : C} (k : W ⟶ X) (h : ∀ j₁ j₂, k ≫ f j₁ = k ≫ f j₂) : {l : W ⟶ wide_equalizer f // l ≫ wide_equalizer.ι f = k}
⟨wide_equalizer.lift k h, wide_equalizer.lift_ι _ _⟩
def
category_theory.limits.wide_equalizer.lift'
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
A morphism `k : W ⟶ X` satisfying `∀ j₁ j₂, k ≫ f j₁ = k ≫ f j₂` induces a morphism `l : W ⟶ wide_equalizer f` satisfying `l ≫ wide_equalizer.ι f = k`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
wide_equalizer.hom_ext [nonempty J] {W : C} {k l : W ⟶ wide_equalizer f} (h : k ≫ wide_equalizer.ι f = l ≫ wide_equalizer.ι f) : k = l
trident.is_limit.hom_ext (limit.is_limit _) h
lemma
category_theory.limits.wide_equalizer.hom_ext
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
Two maps into a wide equalizer are equal if they are are equal when composed with the wide equalizer map.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
wide_equalizer.ι_mono [nonempty J] : mono (wide_equalizer.ι f)
{ right_cancellation := λ Z h k w, wide_equalizer.hom_ext w }
instance
category_theory.limits.wide_equalizer.ι_mono
category_theory.limits.shapes
src/category_theory/limits/shapes/wide_equalizers.lean
[ "category_theory.limits.has_limits", "category_theory.limits.shapes.equalizers" ]
[]
A wide equalizer morphism is a monomorphism
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83