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has_pushout_of_right_factors_epi (f : X ⟶ Y) : has_pushout h (h ≫ f)
by { conv { congr, rw ←category.comp_id h, }, apply_instance }
instance
category_theory.limits.has_pushout_of_right_factors_epi
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pushout_inr_iso_of_right_factors_epi (f : X ⟶ Y) : is_iso (pushout.inr : _ ⟶ pushout h (h ≫ f))
begin convert (congr_arg is_iso (show pushout.inr ≫ _ = _, from colimit.iso_colimit_cocone_ι_inv ⟨_, pushout_is_pushout_of_epi_comp (𝟙 _) f h⟩ walking_span.right)).mp infer_instance; exact (category.comp_id _).symm end
instance
category_theory.limits.pushout_inr_iso_of_right_factors_epi
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pushout_cocone_of_right_iso : pushout_cocone f g
pushout_cocone.mk (𝟙 _) (inv g ≫ f) $ by simp
def
category_theory.limits.pushout_cocone_of_right_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
If `f : X ⟶ Z` is iso, then `Y ⨿[X] Z ≅ Y`. This is the explicit colimit cocone.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pushout_cocone_of_right_iso_X : (pushout_cocone_of_right_iso f g).X = Y
rfl
lemma
category_theory.limits.pushout_cocone_of_right_iso_X
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pushout_cocone_of_right_iso_inl : (pushout_cocone_of_right_iso f g).inl = 𝟙 _
rfl
lemma
category_theory.limits.pushout_cocone_of_right_iso_inl
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pushout_cocone_of_right_iso_inr : (pushout_cocone_of_right_iso f g).inr = inv g ≫ f
rfl
lemma
category_theory.limits.pushout_cocone_of_right_iso_inr
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pushout_cocone_of_right_iso_ι_app_none : (pushout_cocone_of_right_iso f g).ι.app none = f
by { delta pushout_cocone_of_right_iso, simp }
lemma
category_theory.limits.pushout_cocone_of_right_iso_ι_app_none
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pushout_cocone_of_right_iso_ι_app_left : (pushout_cocone_of_right_iso f g).ι.app left = 𝟙 _
rfl
lemma
category_theory.limits.pushout_cocone_of_right_iso_ι_app_left
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pushout_cocone_of_right_iso_ι_app_right : (pushout_cocone_of_right_iso f g).ι.app right = inv g ≫ f
rfl
lemma
category_theory.limits.pushout_cocone_of_right_iso_ι_app_right
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pushout_cocone_of_right_iso_is_limit : is_colimit (pushout_cocone_of_right_iso f g)
pushout_cocone.is_colimit_aux' _ (λ s, ⟨s.inl, by simp [←s.condition]⟩)
def
category_theory.limits.pushout_cocone_of_right_iso_is_limit
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
Verify that the constructed cocone is indeed a colimit.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_pushout_of_right_iso : has_pushout f g
⟨⟨⟨_, pushout_cocone_of_right_iso_is_limit f g⟩⟩⟩
lemma
category_theory.limits.has_pushout_of_right_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pushout_inl_iso_of_right_iso : is_iso (pushout.inl : _ ⟶ pushout f g)
begin refine ⟨⟨pushout.desc (𝟙 _) (inv g ≫ f) (by simp), (by simp), _⟩⟩, ext, { simp [←pushout.condition] }, { simp [pushout.condition] }, end
instance
category_theory.limits.pushout_inl_iso_of_right_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_pushout_of_left_factors_epi (f : X ⟶ Y) : has_pushout (h ≫ f) h
by { conv { congr, skip, rw ←category.comp_id h, }, apply_instance }
instance
category_theory.limits.has_pushout_of_left_factors_epi
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pushout_inl_iso_of_left_factors_epi (f : X ⟶ Y) : is_iso (pushout.inl : _ ⟶ pushout (h ≫ f) h)
begin convert (congr_arg is_iso (show pushout.inl ≫ _ = _, from colimit.iso_colimit_cocone_ι_inv ⟨_, pushout_is_pushout_of_epi_comp f (𝟙 _) h⟩ walking_span.left)).mp infer_instance; exact (category.comp_id _).symm end
instance
category_theory.limits.pushout_inl_iso_of_left_factors_epi
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_kernel_pair_of_mono [mono f] : has_pullback f f
⟨⟨⟨_, pullback_cone.is_limit_mk_id_id f⟩⟩⟩
instance
category_theory.limits.has_kernel_pair_of_mono
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fst_eq_snd_of_mono_eq [mono f] : (pullback.fst : pullback f f ⟶ _) = pullback.snd
((pullback_cone.is_limit_mk_id_id f).fac (get_limit_cone (cospan f f)).cone left).symm.trans ((pullback_cone.is_limit_mk_id_id f).fac (get_limit_cone (cospan f f)).cone right : _)
lemma
category_theory.limits.fst_eq_snd_of_mono_eq
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_symmetry_hom_of_mono_eq [mono f] : (pullback_symmetry f f).hom = 𝟙 _
by ext; simp [fst_eq_snd_of_mono_eq]
lemma
category_theory.limits.pullback_symmetry_hom_of_mono_eq
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
fst_iso_of_mono_eq [mono f] : is_iso (pullback.fst : pullback f f ⟶ _)
begin refine ⟨⟨pullback.lift (𝟙 _) (𝟙 _) (by simp), _, by simp⟩⟩, ext, { simp }, { simp [fst_eq_snd_of_mono_eq] } end
instance
category_theory.limits.fst_iso_of_mono_eq
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
snd_iso_of_mono_eq [mono f] : is_iso (pullback.snd : pullback f f ⟶ _)
by { rw ← fst_eq_snd_of_mono_eq, apply_instance }
instance
category_theory.limits.snd_iso_of_mono_eq
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_cokernel_pair_of_epi [epi f] : has_pushout f f
⟨⟨⟨_, pushout_cocone.is_colimit_mk_id_id f⟩⟩⟩
instance
category_theory.limits.has_cokernel_pair_of_epi
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inl_eq_inr_of_epi_eq [epi f] : (pushout.inl : _ ⟶ pushout f f) = pushout.inr
((pushout_cocone.is_colimit_mk_id_id f).fac (get_colimit_cocone (span f f)).cocone left).symm.trans ((pushout_cocone.is_colimit_mk_id_id f).fac (get_colimit_cocone (span f f)).cocone right : _)
lemma
category_theory.limits.inl_eq_inr_of_epi_eq
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_symmetry_hom_of_epi_eq [epi f] : (pushout_symmetry f f).hom = 𝟙 _
by ext; simp [inl_eq_inr_of_epi_eq]
lemma
category_theory.limits.pullback_symmetry_hom_of_epi_eq
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inl_iso_of_epi_eq [epi f] : is_iso (pushout.inl : _ ⟶ pushout f f)
begin refine ⟨⟨pushout.desc (𝟙 _) (𝟙 _) (by simp), by simp, _⟩⟩, ext, { simp }, { simp [inl_eq_inr_of_epi_eq] } end
instance
category_theory.limits.inl_iso_of_epi_eq
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inr_iso_of_epi_eq [epi f] : is_iso (pushout.inr : _ ⟶ pushout f f)
by { rw ← inl_eq_inr_of_epi_eq, apply_instance }
instance
category_theory.limits.inr_iso_of_epi_eq
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
big_square_is_pullback (H : is_limit (pullback_cone.mk _ _ h₂)) (H' : is_limit (pullback_cone.mk _ _ h₁)) : is_limit (pullback_cone.mk _ _ (show i₁ ≫ g₁ ≫ g₂ = (f₁ ≫ f₂) ≫ i₃, by rw [← category.assoc, h₁, category.assoc, h₂, category.assoc]))
begin fapply pullback_cone.is_limit_aux', intro s, have : (s.fst ≫ g₁) ≫ g₂ = s.snd ≫ i₃ := by rw [← s.condition, category.assoc], rcases pullback_cone.is_limit.lift' H (s.fst ≫ g₁) s.snd this with ⟨l₁, hl₁, hl₁'⟩, rcases pullback_cone.is_limit.lift' H' s.fst l₁ hl₁.symm with ⟨l₂, hl₂, hl₂'⟩, use l₂, use ...
def
category_theory.limits.big_square_is_pullback
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
Given X₁ - f₁ -> X₂ - f₂ -> X₃ | | | i₁ i₂ i₃ ∨ ∨ ∨ Y₁ - g₁ -> Y₂ - g₂ -> Y₃ Then the big square is a pullback if both the small squares are.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
big_square_is_pushout (H : is_colimit (pushout_cocone.mk _ _ h₂)) (H' : is_colimit (pushout_cocone.mk _ _ h₁)) : is_colimit (pushout_cocone.mk _ _ (show i₁ ≫ g₁ ≫ g₂ = (f₁ ≫ f₂) ≫ i₃, by rw [← category.assoc, h₁, category.assoc, h₂, category.assoc]))
begin fapply pushout_cocone.is_colimit_aux', intro s, have : i₁ ≫ s.inl = f₁ ≫ (f₂ ≫ s.inr) := by rw [s.condition, category.assoc], rcases pushout_cocone.is_colimit.desc' H' s.inl (f₂ ≫ s.inr) this with ⟨l₁, hl₁, hl₁'⟩, rcases pushout_cocone.is_colimit.desc' H l₁ s.inr hl₁' with ⟨l₂, hl₂, hl₂'⟩, use l₂, u...
def
category_theory.limits.big_square_is_pushout
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
Given X₁ - f₁ -> X₂ - f₂ -> X₃ | | | i₁ i₂ i₃ ∨ ∨ ∨ Y₁ - g₁ -> Y₂ - g₂ -> Y₃ Then the big square is a pushout if both the small squares are.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
left_square_is_pullback (H : is_limit (pullback_cone.mk _ _ h₂)) (H' : is_limit (pullback_cone.mk _ _ (show i₁ ≫ g₁ ≫ g₂ = (f₁ ≫ f₂) ≫ i₃, by rw [← category.assoc, h₁, category.assoc, h₂, category.assoc]))) : is_limit (pullback_cone.mk _ _ h₁)
begin fapply pullback_cone.is_limit_aux', intro s, have : s.fst ≫ g₁ ≫ g₂ = (s.snd ≫ f₂) ≫ i₃ := by { rw [← category.assoc, s.condition, category.assoc, category.assoc, h₂] }, rcases pullback_cone.is_limit.lift' H' s.fst (s.snd ≫ f₂) this with ⟨l₁, hl₁, hl₁'⟩, use l₁, use hl₁, split, { apply pullback_...
def
category_theory.limits.left_square_is_pullback
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
Given X₁ - f₁ -> X₂ - f₂ -> X₃ | | | i₁ i₂ i₃ ∨ ∨ ∨ Y₁ - g₁ -> Y₂ - g₂ -> Y₃ Then the left square is a pullback if the right square and the big square are.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
right_square_is_pushout (H : is_colimit (pushout_cocone.mk _ _ h₁)) (H' : is_colimit (pushout_cocone.mk _ _ (show i₁ ≫ g₁ ≫ g₂ = (f₁ ≫ f₂) ≫ i₃, by rw [← category.assoc, h₁, category.assoc, h₂, category.assoc]))) : is_colimit (pushout_cocone.mk _ _ h₂)
begin fapply pushout_cocone.is_colimit_aux', intro s, have : i₁ ≫ g₁ ≫ s.inl = (f₁ ≫ f₂) ≫ s.inr := by { rw [category.assoc, ← s.condition, ← category.assoc, ← category.assoc, h₁] }, rcases pushout_cocone.is_colimit.desc' H' (g₁ ≫ s.inl) s.inr this with ⟨l₁, hl₁, hl₁'⟩, dsimp at *, use l₁, refine ⟨_,_,_...
def
category_theory.limits.right_square_is_pushout
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
Given X₁ - f₁ -> X₂ - f₂ -> X₃ | | | i₁ i₂ i₃ ∨ ∨ ∨ Y₁ - g₁ -> Y₂ - g₂ -> Y₃ Then the right square is a pushout if the left square and the big square are.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_right_pullback_fst_iso : pullback f' (pullback.fst : pullback f g ⟶ _) ≅ pullback (f' ≫ f) g
begin let := big_square_is_pullback (pullback.snd : pullback f' (pullback.fst : pullback f g ⟶ _) ⟶ _) pullback.snd f' f pullback.fst pullback.fst g pullback.condition pullback.condition (pullback_is_pullback _ _) (pullback_is_pullback _ _), exact (this.cone_point_unique_up_to_iso (pullback_is_pullback ...
def
category_theory.limits.pullback_right_pullback_fst_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The canonical isomorphism `W ×[X] (X ×[Z] Y) ≅ W ×[Z] Y`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_right_pullback_fst_iso_hom_fst : (pullback_right_pullback_fst_iso f g f').hom ≫ pullback.fst = pullback.fst
is_limit.cone_point_unique_up_to_iso_hom_comp _ _ walking_cospan.left
lemma
category_theory.limits.pullback_right_pullback_fst_iso_hom_fst
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_right_pullback_fst_iso_hom_snd : (pullback_right_pullback_fst_iso f g f').hom ≫ pullback.snd = pullback.snd ≫ pullback.snd
is_limit.cone_point_unique_up_to_iso_hom_comp _ _ walking_cospan.right
lemma
category_theory.limits.pullback_right_pullback_fst_iso_hom_snd
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_right_pullback_fst_iso_inv_fst : (pullback_right_pullback_fst_iso f g f').inv ≫ pullback.fst = pullback.fst
is_limit.cone_point_unique_up_to_iso_inv_comp _ _ walking_cospan.left
lemma
category_theory.limits.pullback_right_pullback_fst_iso_inv_fst
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_right_pullback_fst_iso_inv_snd_snd : (pullback_right_pullback_fst_iso f g f').inv ≫ pullback.snd ≫ pullback.snd = pullback.snd
is_limit.cone_point_unique_up_to_iso_inv_comp _ _ walking_cospan.right
lemma
category_theory.limits.pullback_right_pullback_fst_iso_inv_snd_snd
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_right_pullback_fst_iso_inv_snd_fst : (pullback_right_pullback_fst_iso f g f').inv ≫ pullback.snd ≫ pullback.fst = pullback.fst ≫ f'
begin rw ← pullback.condition, exact pullback_right_pullback_fst_iso_inv_fst_assoc _ _ _ _ end
lemma
category_theory.limits.pullback_right_pullback_fst_iso_inv_snd_fst
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pushout_left_pushout_inr_iso : pushout (pushout.inr : _ ⟶ pushout f g) g' ≅ pushout f (g ≫ g')
((big_square_is_pushout g g' _ _ f _ _ pushout.condition pushout.condition (pushout_is_pushout _ _) (pushout_is_pushout _ _)) .cocone_point_unique_up_to_iso (pushout_is_pushout _ _) : _)
def
category_theory.limits.pushout_left_pushout_inr_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The canonical isomorphism `(Y ⨿[X] Z) ⨿[Z] W ≅ Y ×[X] W`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inl_pushout_left_pushout_inr_iso_inv : pushout.inl ≫ (pushout_left_pushout_inr_iso f g g').inv = pushout.inl ≫ pushout.inl
((big_square_is_pushout g g' _ _ f _ _ pushout.condition pushout.condition (pushout_is_pushout _ _) (pushout_is_pushout _ _)) .comp_cocone_point_unique_up_to_iso_inv (pushout_is_pushout _ _) walking_span.left : _)
lemma
category_theory.limits.inl_pushout_left_pushout_inr_iso_inv
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inr_pushout_left_pushout_inr_iso_hom : pushout.inr ≫ (pushout_left_pushout_inr_iso f g g').hom = pushout.inr
((big_square_is_pushout g g' _ _ f _ _ pushout.condition pushout.condition (pushout_is_pushout _ _) (pushout_is_pushout _ _)) .comp_cocone_point_unique_up_to_iso_hom (pushout_is_pushout _ _) walking_span.right : _)
lemma
category_theory.limits.inr_pushout_left_pushout_inr_iso_hom
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inr_pushout_left_pushout_inr_iso_inv : pushout.inr ≫ (pushout_left_pushout_inr_iso f g g').inv = pushout.inr
by rw [iso.comp_inv_eq, inr_pushout_left_pushout_inr_iso_hom]
lemma
category_theory.limits.inr_pushout_left_pushout_inr_iso_inv
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inl_inl_pushout_left_pushout_inr_iso_hom : pushout.inl ≫ pushout.inl ≫ (pushout_left_pushout_inr_iso f g g').hom = pushout.inl
by rw [← category.assoc, ← iso.eq_comp_inv, inl_pushout_left_pushout_inr_iso_inv]
lemma
category_theory.limits.inl_inl_pushout_left_pushout_inr_iso_hom
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inr_inl_pushout_left_pushout_inr_iso_hom : pushout.inr ≫ pushout.inl ≫ (pushout_left_pushout_inr_iso f g g').hom = g' ≫ pushout.inr
by rw [← category.assoc, ← iso.eq_comp_inv, category.assoc, inr_pushout_left_pushout_inr_iso_inv, pushout.condition]
lemma
category_theory.limits.inr_inl_pushout_left_pushout_inr_iso_hom
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_pullback_left_is_pullback [has_pullback (g₂ ≫ f₃) f₄] : is_limit (pullback_cone.mk l₁ l₂ (show l₁ ≫ g₂ = l₂ ≫ g₃, from (pullback.lift_fst _ _ _).symm))
begin apply left_square_is_pullback, exact pullback_is_pullback f₃ f₄, convert pullback_is_pullback (g₂ ≫ f₃) f₄, rw pullback.lift_snd end
def
category_theory.limits.pullback_pullback_left_is_pullback
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
`(X₁ ×[Y₁] X₂) ×[Y₂] X₃` is the pullback `(X₁ ×[Y₁] X₂) ×[X₂] (X₂ ×[Y₂] X₃)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_assoc_is_pullback [has_pullback (g₂ ≫ f₃) f₄] : is_limit (pullback_cone.mk (l₁ ≫ g₁) l₂ (show (l₁ ≫ g₁) ≫ f₁ = l₂ ≫ (g₃ ≫ f₂), by rw [pullback.lift_fst_assoc, category.assoc, category.assoc, pullback.condition]))
begin apply pullback_cone.flip_is_limit, apply big_square_is_pullback, { apply pullback_cone.flip_is_limit, exact pullback_is_pullback f₁ f₂ }, { apply pullback_cone.flip_is_limit, apply pullback_pullback_left_is_pullback }, { exact pullback.lift_fst _ _ _ }, { exact pullback.condition.symm } end
def
category_theory.limits.pullback_assoc_is_pullback
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
`(X₁ ×[Y₁] X₂) ×[Y₂] X₃` is the pullback `X₁ ×[Y₁] (X₂ ×[Y₂] X₃)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_pullback_assoc [has_pullback (g₂ ≫ f₃) f₄] : has_pullback f₁ (g₃ ≫ f₂)
⟨⟨⟨_, pullback_assoc_is_pullback f₁ f₂ f₃ f₄⟩⟩⟩
lemma
category_theory.limits.has_pullback_assoc
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_pullback_right_is_pullback [has_pullback f₁ (g₃ ≫ f₂)] : is_limit (pullback_cone.mk l₁' l₂' (show l₁' ≫ g₂ = l₂' ≫ g₃, from pullback.lift_snd _ _ _))
begin apply pullback_cone.flip_is_limit, apply left_square_is_pullback, { apply pullback_cone.flip_is_limit, exact pullback_is_pullback f₁ f₂ }, { apply pullback_cone.flip_is_limit, convert pullback_is_pullback f₁ (g₃ ≫ f₂), rw pullback.lift_fst }, { exact pullback.condition.symm } end
def
category_theory.limits.pullback_pullback_right_is_pullback
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
`X₁ ×[Y₁] (X₂ ×[Y₂] X₃)` is the pullback `(X₁ ×[Y₁] X₂) ×[X₂] (X₂ ×[Y₂] X₃)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_assoc_symm_is_pullback [has_pullback f₁ (g₃ ≫ f₂)] : is_limit (pullback_cone.mk l₁' (l₂' ≫ g₄) (show l₁' ≫ (g₂ ≫ f₃) = (l₂' ≫ g₄) ≫ f₄, by rw [pullback.lift_snd_assoc, category.assoc, category.assoc, pullback.condition]))
begin apply big_square_is_pullback, exact pullback_is_pullback f₃ f₄, apply pullback_pullback_right_is_pullback end
def
category_theory.limits.pullback_assoc_symm_is_pullback
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
`X₁ ×[Y₁] (X₂ ×[Y₂] X₃)` is the pullback `(X₁ ×[Y₁] X₂) ×[Y₂] X₃`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_pullback_assoc_symm [has_pullback f₁ (g₃ ≫ f₂)] : has_pullback (g₂ ≫ f₃) f₄
⟨⟨⟨_, pullback_assoc_symm_is_pullback f₁ f₂ f₃ f₄⟩⟩⟩
lemma
category_theory.limits.has_pullback_assoc_symm
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_assoc : pullback (pullback.snd ≫ f₃ : pullback f₁ f₂ ⟶ _) f₄ ≅ pullback f₁ (pullback.fst ≫ f₂ : pullback f₃ f₄ ⟶ _)
(pullback_pullback_left_is_pullback f₁ f₂ f₃ f₄).cone_point_unique_up_to_iso (pullback_pullback_right_is_pullback f₁ f₂ f₃ f₄)
def
category_theory.limits.pullback_assoc
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The canonical isomorphism `(X₁ ×[Y₁] X₂) ×[Y₂] X₃ ≅ X₁ ×[Y₁] (X₂ ×[Y₂] X₃)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_assoc_inv_fst_fst : (pullback_assoc f₁ f₂ f₃ f₄).inv ≫ pullback.fst ≫ pullback.fst = pullback.fst
begin transitivity l₁' ≫ pullback.fst, rw ← category.assoc, congr' 1, exact is_limit.cone_point_unique_up_to_iso_inv_comp _ _ walking_cospan.left, exact pullback.lift_fst _ _ _, end
lemma
category_theory.limits.pullback_assoc_inv_fst_fst
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_assoc_hom_fst : (pullback_assoc f₁ f₂ f₃ f₄).hom ≫ pullback.fst = pullback.fst ≫ pullback.fst
by rw [← iso.eq_inv_comp, pullback_assoc_inv_fst_fst]
lemma
category_theory.limits.pullback_assoc_hom_fst
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_assoc_hom_snd_fst : (pullback_assoc f₁ f₂ f₃ f₄).hom ≫ pullback.snd ≫ pullback.fst = pullback.fst ≫ pullback.snd
begin transitivity l₂ ≫ pullback.fst, rw ← category.assoc, congr' 1, exact is_limit.cone_point_unique_up_to_iso_hom_comp _ _ walking_cospan.right, exact pullback.lift_fst _ _ _, end
lemma
category_theory.limits.pullback_assoc_hom_snd_fst
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_assoc_hom_snd_snd : (pullback_assoc f₁ f₂ f₃ f₄).hom ≫ pullback.snd ≫ pullback.snd = pullback.snd
begin transitivity l₂ ≫ pullback.snd, rw ← category.assoc, congr' 1, exact is_limit.cone_point_unique_up_to_iso_hom_comp _ _ walking_cospan.right, exact pullback.lift_snd _ _ _, end
lemma
category_theory.limits.pullback_assoc_hom_snd_snd
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_assoc_inv_fst_snd : (pullback_assoc f₁ f₂ f₃ f₄).inv ≫ pullback.fst ≫ pullback.snd = pullback.snd ≫ pullback.fst
by rw [iso.inv_comp_eq, pullback_assoc_hom_snd_fst]
lemma
category_theory.limits.pullback_assoc_inv_fst_snd
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pullback_assoc_inv_snd : (pullback_assoc f₁ f₂ f₃ f₄).inv ≫ pullback.snd = pullback.snd ≫ pullback.snd
by rw [iso.inv_comp_eq, pullback_assoc_hom_snd_snd]
lemma
category_theory.limits.pullback_assoc_inv_snd
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pushout_pushout_left_is_pushout [has_pushout (g₃ ≫ f₂) g₄] : is_colimit (pushout_cocone.mk l₁' l₂' (show f₂ ≫ l₁' = f₃ ≫ l₂', from (pushout.inl_desc _ _ _).symm))
begin apply pushout_cocone.flip_is_colimit, apply right_square_is_pushout, { apply pushout_cocone.flip_is_colimit, exact pushout_is_pushout _ _ }, { apply pushout_cocone.flip_is_colimit, convert pushout_is_pushout (g₃ ≫ f₂) g₄, exact pushout.inr_desc _ _ _ }, { exact pushout.condition.symm } end
def
category_theory.limits.pushout_pushout_left_is_pushout
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
`(X₁ ⨿[Z₁] X₂) ⨿[Z₂] X₃` is the pushout `(X₁ ⨿[Z₁] X₂) ×[X₂] (X₂ ⨿[Z₂] X₃)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pushout_assoc_is_pushout [has_pushout (g₃ ≫ f₂) g₄] : is_colimit (pushout_cocone.mk (f₁ ≫ l₁') l₂' (show g₁ ≫ (f₁ ≫ l₁') = (g₂ ≫ f₃) ≫ l₂', by rw [category.assoc, pushout.inl_desc, pushout.condition_assoc]))
begin apply big_square_is_pushout, { apply pushout_pushout_left_is_pushout }, { exact pushout_is_pushout _ _ } end
def
category_theory.limits.pushout_assoc_is_pushout
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
`(X₁ ⨿[Z₁] X₂) ⨿[Z₂] X₃` is the pushout `X₁ ⨿[Z₁] (X₂ ⨿[Z₂] X₃)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_pushout_assoc [has_pushout (g₃ ≫ f₂) g₄] : has_pushout g₁ (g₂ ≫ f₃)
⟨⟨⟨_, pushout_assoc_is_pushout g₁ g₂ g₃ g₄⟩⟩⟩
lemma
category_theory.limits.has_pushout_assoc
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pushout_pushout_right_is_pushout [has_pushout g₁ (g₂ ≫ f₃)] : is_colimit (pushout_cocone.mk l₁ l₂ (show f₂ ≫ l₁ = f₃ ≫ l₂, from pushout.inr_desc _ _ _))
begin apply right_square_is_pushout, { exact pushout_is_pushout _ _ }, { convert pushout_is_pushout g₁ (g₂ ≫ f₃), rw pushout.inl_desc } end
def
category_theory.limits.pushout_pushout_right_is_pushout
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
`X₁ ⨿[Z₁] (X₂ ⨿[Z₂] X₃)` is the pushout `(X₁ ⨿[Z₁] X₂) ×[X₂] (X₂ ⨿[Z₂] X₃)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pushout_assoc_symm_is_pushout [has_pushout g₁ (g₂ ≫ f₃)] : is_colimit (pushout_cocone.mk l₁ (f₄ ≫ l₂) ((show (g₃ ≫ f₂) ≫ l₁ = g₄ ≫ (f₄ ≫ l₂), by rw [category.assoc, pushout.inr_desc, pushout.condition_assoc])))
begin apply pushout_cocone.flip_is_colimit, apply big_square_is_pushout, { apply pushout_cocone.flip_is_colimit, apply pushout_pushout_right_is_pushout }, { apply pushout_cocone.flip_is_colimit, exact pushout_is_pushout _ _ }, { exact pushout.condition.symm }, { exact (pushout.inr_desc _ _ _).symm }...
def
category_theory.limits.pushout_assoc_symm_is_pushout
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
`X₁ ⨿[Z₁] (X₂ ⨿[Z₂] X₃)` is the pushout `(X₁ ⨿[Z₁] X₂) ⨿[Z₂] X₃`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_pushout_assoc_symm [has_pushout g₁ (g₂ ≫ f₃)] : has_pushout (g₃ ≫ f₂) g₄
⟨⟨⟨_, pushout_assoc_symm_is_pushout g₁ g₂ g₃ g₄⟩⟩⟩
lemma
category_theory.limits.has_pushout_assoc_symm
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pushout_assoc : pushout (g₃ ≫ pushout.inr : _ ⟶ pushout g₁ g₂) g₄ ≅ pushout g₁ (g₂ ≫ pushout.inl : _ ⟶ pushout g₃ g₄)
(pushout_pushout_left_is_pushout g₁ g₂ g₃ g₄).cocone_point_unique_up_to_iso (pushout_pushout_right_is_pushout g₁ g₂ g₃ g₄)
def
category_theory.limits.pushout_assoc
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The canonical isomorphism `(X₁ ⨿[Z₁] X₂) ⨿[Z₂] X₃ ≅ X₁ ⨿[Z₁] (X₂ ⨿[Z₂] X₃)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inl_inl_pushout_assoc_hom : pushout.inl ≫ pushout.inl ≫ (pushout_assoc g₁ g₂ g₃ g₄).hom = pushout.inl
begin transitivity f₁ ≫ l₁, { congr' 1, exact (pushout_pushout_left_is_pushout g₁ g₂ g₃ g₄) .comp_cocone_point_unique_up_to_iso_hom _ walking_cospan.left }, { exact pushout.inl_desc _ _ _ } end
lemma
category_theory.limits.inl_inl_pushout_assoc_hom
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inr_inl_pushout_assoc_hom : pushout.inr ≫ pushout.inl ≫ (pushout_assoc g₁ g₂ g₃ g₄).hom = pushout.inl ≫ pushout.inr
begin transitivity f₂ ≫ l₁, { congr' 1, exact (pushout_pushout_left_is_pushout g₁ g₂ g₃ g₄) .comp_cocone_point_unique_up_to_iso_hom _ walking_cospan.left }, { exact pushout.inr_desc _ _ _ } end
lemma
category_theory.limits.inr_inl_pushout_assoc_hom
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inr_inr_pushout_assoc_inv : pushout.inr ≫ pushout.inr ≫ (pushout_assoc g₁ g₂ g₃ g₄).inv = pushout.inr
begin transitivity f₄ ≫ l₂', { congr' 1, exact (pushout_pushout_left_is_pushout g₁ g₂ g₃ g₄).comp_cocone_point_unique_up_to_iso_inv (pushout_pushout_right_is_pushout g₁ g₂ g₃ g₄) walking_cospan.right }, { exact pushout.inr_desc _ _ _ } end
lemma
category_theory.limits.inr_inr_pushout_assoc_inv
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inl_pushout_assoc_inv : pushout.inl ≫ (pushout_assoc g₁ g₂ g₃ g₄).inv = pushout.inl ≫ pushout.inl
by rw [iso.comp_inv_eq, category.assoc, inl_inl_pushout_assoc_hom]
lemma
category_theory.limits.inl_pushout_assoc_inv
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inl_inr_pushout_assoc_inv : pushout.inl ≫ pushout.inr ≫ (pushout_assoc g₁ g₂ g₃ g₄).inv = pushout.inr ≫ pushout.inl
by rw [← category.assoc, iso.comp_inv_eq, category.assoc, inr_inl_pushout_assoc_hom]
lemma
category_theory.limits.inl_inr_pushout_assoc_inv
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inr_pushout_assoc_hom : pushout.inr ≫ (pushout_assoc g₁ g₂ g₃ g₄).hom = pushout.inr ≫ pushout.inr
by rw [← iso.eq_comp_inv, category.assoc, inr_inr_pushout_assoc_inv]
lemma
category_theory.limits.inr_pushout_assoc_hom
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_pullbacks
has_limits_of_shape walking_cospan C
abbreviation
category_theory.limits.has_pullbacks
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
`has_pullbacks` represents a choice of pullback for every pair of morphisms See <https://stacks.math.columbia.edu/tag/001W>
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_pushouts
has_colimits_of_shape walking_span C
abbreviation
category_theory.limits.has_pushouts
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
`has_pushouts` represents a choice of pushout for every pair of morphisms
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_pullbacks_of_has_limit_cospan [Π {X Y Z : C} {f : X ⟶ Z} {g : Y ⟶ Z}, has_limit (cospan f g)] : has_pullbacks C
{ has_limit := λ F, has_limit_of_iso (diagram_iso_cospan F).symm }
lemma
category_theory.limits.has_pullbacks_of_has_limit_cospan
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
If `C` has all limits of diagrams `cospan f g`, then it has all pullbacks
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_pushouts_of_has_colimit_span [Π {X Y Z : C} {f : X ⟶ Y} {g : X ⟶ Z}, has_colimit (span f g)] : has_pushouts C
{ has_colimit := λ F, has_colimit_of_iso (diagram_iso_span F) }
lemma
category_theory.limits.has_pushouts_of_has_colimit_span
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
If `C` has all colimits of diagrams `span f g`, then it has all pushouts
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_span_op_equiv : walking_spanᵒᵖ ≌ walking_cospan
wide_pushout_shape_op_equiv _
def
category_theory.limits.walking_span_op_equiv
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The duality equivalence `walking_spanᵒᵖ ≌ walking_cospan`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_cospan_op_equiv : walking_cospanᵒᵖ ≌ walking_span
wide_pullback_shape_op_equiv _
def
category_theory.limits.walking_cospan_op_equiv
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
The duality equivalence `walking_cospanᵒᵖ ≌ walking_span`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_pullbacks_of_has_wide_pullbacks [has_wide_pullbacks.{w} C] : has_pullbacks C
begin haveI := has_wide_pullbacks_shrink.{0 w} C, apply_instance end
instance
category_theory.limits.has_pullbacks_of_has_wide_pullbacks
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
Having wide pullback at any universe level implies having binary pullbacks.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
base_change [has_pullbacks C] {X Y : C} (f : X ⟶ Y) : over Y ⥤ over X
{ obj := λ g, over.mk (pullback.snd : pullback g.hom f ⟶ _), map := λ g₁ g₂ i, over.hom_mk (pullback.map _ _ _ _ i.left (𝟙 _) (𝟙 _) (by simp) (by simp)) (by simp) }
def
category_theory.limits.base_change
category_theory.limits.shapes
src/category_theory/limits/shapes/pullbacks.lean
[ "category_theory.limits.shapes.wide_pullbacks", "category_theory.limits.shapes.binary_products" ]
[]
Given a morphism `f : X ⟶ Y`, we can take morphisms over `Y` to morphisms over `X` via pullbacks. This is right adjoint to `over.map` (TODO)
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_reflexive_pair (f g : A ⟶ B) : Prop
(common_section [] : ∃ (s : B ⟶ A), s ≫ f = 𝟙 B ∧ s ≫ g = 𝟙 B)
class
category_theory.is_reflexive_pair
category_theory.limits.shapes
src/category_theory/limits/shapes/reflexive.lean
[ "category_theory.limits.shapes.equalizers", "category_theory.limits.shapes.kernel_pair" ]
[]
The pair `f g : A ⟶ B` is reflexive if there is a morphism `B ⟶ A` which is a section for both.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_coreflexive_pair (f g : A ⟶ B) : Prop
(common_retraction [] : ∃ (s : B ⟶ A), f ≫ s = 𝟙 A ∧ g ≫ s = 𝟙 A)
class
category_theory.is_coreflexive_pair
category_theory.limits.shapes
src/category_theory/limits/shapes/reflexive.lean
[ "category_theory.limits.shapes.equalizers", "category_theory.limits.shapes.kernel_pair" ]
[]
The pair `f g : A ⟶ B` is coreflexive if there is a morphism `B ⟶ A` which is a retraction for both.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_reflexive_pair.mk' (s : B ⟶ A) (sf : s ≫ f = 𝟙 B) (sg : s ≫ g = 𝟙 B) : is_reflexive_pair f g
⟨⟨s, sf, sg⟩⟩
lemma
category_theory.is_reflexive_pair.mk'
category_theory.limits.shapes
src/category_theory/limits/shapes/reflexive.lean
[ "category_theory.limits.shapes.equalizers", "category_theory.limits.shapes.kernel_pair" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_coreflexive_pair.mk' (s : B ⟶ A) (fs : f ≫ s = 𝟙 A) (gs : g ≫ s = 𝟙 A) : is_coreflexive_pair f g
⟨⟨s, fs, gs⟩⟩
lemma
category_theory.is_coreflexive_pair.mk'
category_theory.limits.shapes
src/category_theory/limits/shapes/reflexive.lean
[ "category_theory.limits.shapes.equalizers", "category_theory.limits.shapes.kernel_pair" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
common_section (f g : A ⟶ B) [is_reflexive_pair f g] : B ⟶ A
(is_reflexive_pair.common_section f g).some
def
category_theory.common_section
category_theory.limits.shapes
src/category_theory/limits/shapes/reflexive.lean
[ "category_theory.limits.shapes.equalizers", "category_theory.limits.shapes.kernel_pair" ]
[]
Get the common section for a reflexive pair.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
section_comp_left (f g : A ⟶ B) [is_reflexive_pair f g] : common_section f g ≫ f = 𝟙 B
(is_reflexive_pair.common_section f g).some_spec.1
lemma
category_theory.section_comp_left
category_theory.limits.shapes
src/category_theory/limits/shapes/reflexive.lean
[ "category_theory.limits.shapes.equalizers", "category_theory.limits.shapes.kernel_pair" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
section_comp_right (f g : A ⟶ B) [is_reflexive_pair f g] : common_section f g ≫ g = 𝟙 B
(is_reflexive_pair.common_section f g).some_spec.2
lemma
category_theory.section_comp_right
category_theory.limits.shapes
src/category_theory/limits/shapes/reflexive.lean
[ "category_theory.limits.shapes.equalizers", "category_theory.limits.shapes.kernel_pair" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
common_retraction (f g : A ⟶ B) [is_coreflexive_pair f g] : B ⟶ A
(is_coreflexive_pair.common_retraction f g).some
def
category_theory.common_retraction
category_theory.limits.shapes
src/category_theory/limits/shapes/reflexive.lean
[ "category_theory.limits.shapes.equalizers", "category_theory.limits.shapes.kernel_pair" ]
[]
Get the common retraction for a coreflexive pair.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
left_comp_retraction (f g : A ⟶ B) [is_coreflexive_pair f g] : f ≫ common_retraction f g = 𝟙 A
(is_coreflexive_pair.common_retraction f g).some_spec.1
lemma
category_theory.left_comp_retraction
category_theory.limits.shapes
src/category_theory/limits/shapes/reflexive.lean
[ "category_theory.limits.shapes.equalizers", "category_theory.limits.shapes.kernel_pair" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
right_comp_retraction (f g : A ⟶ B) [is_coreflexive_pair f g] : g ≫ common_retraction f g = 𝟙 A
(is_coreflexive_pair.common_retraction f g).some_spec.2
lemma
category_theory.right_comp_retraction
category_theory.limits.shapes
src/category_theory/limits/shapes/reflexive.lean
[ "category_theory.limits.shapes.equalizers", "category_theory.limits.shapes.kernel_pair" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_kernel_pair.is_reflexive_pair {R : C} {f g : R ⟶ A} {q : A ⟶ B} (h : is_kernel_pair q f g) : is_reflexive_pair f g
is_reflexive_pair.mk' _ (h.lift' _ _ rfl).2.1 (h.lift' _ _ _).2.2
lemma
category_theory.is_kernel_pair.is_reflexive_pair
category_theory.limits.shapes
src/category_theory/limits/shapes/reflexive.lean
[ "category_theory.limits.shapes.equalizers", "category_theory.limits.shapes.kernel_pair" ]
[]
If `f,g` is a kernel pair for some morphism `q`, then it is reflexive.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_reflexive_pair.swap [is_reflexive_pair f g] : is_reflexive_pair g f
is_reflexive_pair.mk' _ (section_comp_right f g) (section_comp_left f g)
lemma
category_theory.is_reflexive_pair.swap
category_theory.limits.shapes
src/category_theory/limits/shapes/reflexive.lean
[ "category_theory.limits.shapes.equalizers", "category_theory.limits.shapes.kernel_pair" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_coreflexive_pair.swap [is_coreflexive_pair f g] : is_coreflexive_pair g f
is_coreflexive_pair.mk' _ (right_comp_retraction f g) (left_comp_retraction f g)
lemma
category_theory.is_coreflexive_pair.swap
category_theory.limits.shapes
src/category_theory/limits/shapes/reflexive.lean
[ "category_theory.limits.shapes.equalizers", "category_theory.limits.shapes.kernel_pair" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_reflexive_coequalizers : Prop
(has_coeq : ∀ ⦃A B : C⦄ (f g : A ⟶ B) [is_reflexive_pair f g], has_coequalizer f g)
class
category_theory.limits.has_reflexive_coequalizers
category_theory.limits.shapes
src/category_theory/limits/shapes/reflexive.lean
[ "category_theory.limits.shapes.equalizers", "category_theory.limits.shapes.kernel_pair" ]
[]
`C` has reflexive coequalizers if it has coequalizers for every reflexive pair.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_coreflexive_equalizers : Prop
(has_eq : ∀ ⦃A B : C⦄ (f g : A ⟶ B) [is_coreflexive_pair f g], has_equalizer f g)
class
category_theory.limits.has_coreflexive_equalizers
category_theory.limits.shapes
src/category_theory/limits/shapes/reflexive.lean
[ "category_theory.limits.shapes.equalizers", "category_theory.limits.shapes.kernel_pair" ]
[]
`C` has coreflexive equalizers if it has equalizers for every coreflexive pair.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_coequalizer_of_common_section [has_reflexive_coequalizers C] {A B : C} {f g : A ⟶ B} (r : B ⟶ A) (rf : r ≫ f = 𝟙 _) (rg : r ≫ g = 𝟙 _) : has_coequalizer f g
begin letI := is_reflexive_pair.mk' r rf rg, apply_instance end
lemma
category_theory.limits.has_coequalizer_of_common_section
category_theory.limits.shapes
src/category_theory/limits/shapes/reflexive.lean
[ "category_theory.limits.shapes.equalizers", "category_theory.limits.shapes.kernel_pair" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_equalizer_of_common_retraction [has_coreflexive_equalizers C] {A B : C} {f g : A ⟶ B} (r : B ⟶ A) (fr : f ≫ r = 𝟙 _) (gr : g ≫ r = 𝟙 _) : has_equalizer f g
begin letI := is_coreflexive_pair.mk' r fr gr, apply_instance end
lemma
category_theory.limits.has_equalizer_of_common_retraction
category_theory.limits.shapes
src/category_theory/limits/shapes/reflexive.lean
[ "category_theory.limits.shapes.equalizers", "category_theory.limits.shapes.kernel_pair" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_reflexive_coequalizers_of_has_coequalizers [has_coequalizers C] : has_reflexive_coequalizers C
{ has_coeq := λ A B f g i, by apply_instance }
instance
category_theory.limits.has_reflexive_coequalizers_of_has_coequalizers
category_theory.limits.shapes
src/category_theory/limits/shapes/reflexive.lean
[ "category_theory.limits.shapes.equalizers", "category_theory.limits.shapes.kernel_pair" ]
[]
If `C` has coequalizers, then it has reflexive coequalizers.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_coreflexive_equalizers_of_has_equalizers [has_equalizers C] : has_coreflexive_equalizers C
{ has_eq := λ A B f g i, by apply_instance }
instance
category_theory.limits.has_coreflexive_equalizers_of_has_equalizers
category_theory.limits.shapes
src/category_theory/limits/shapes/reflexive.lean
[ "category_theory.limits.shapes.equalizers", "category_theory.limits.shapes.kernel_pair" ]
[]
If `C` has equalizers, then it has coreflexive equalizers.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
regular_mono (f : X ⟶ Y)
(Z : C) (left right : Y ⟶ Z) (w : f ≫ left = f ≫ right) (is_limit : is_limit (fork.of_ι f w))
class
category_theory.regular_mono
category_theory.limits.shapes
src/category_theory/limits/shapes/regular_mono.lean
[ "category_theory.limits.shapes.pullbacks", "category_theory.limits.shapes.strong_epi", "category_theory.limits.shapes.equalizers" ]
[]
A regular monomorphism is a morphism which is the equalizer of some parallel pair.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
regular_mono.mono (f : X ⟶ Y) [regular_mono f] : mono f
mono_of_is_limit_fork regular_mono.is_limit
instance
category_theory.regular_mono.mono
category_theory.limits.shapes
src/category_theory/limits/shapes/regular_mono.lean
[ "category_theory.limits.shapes.pullbacks", "category_theory.limits.shapes.strong_epi", "category_theory.limits.shapes.equalizers" ]
[]
Every regular monomorphism is a monomorphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equalizer_regular (g h : X ⟶ Y) [has_limit (parallel_pair g h)] : regular_mono (equalizer.ι g h)
{ Z := Y, left := g, right := h, w := equalizer.condition g h, is_limit := fork.is_limit.mk _ (λ s, limit.lift _ s) (by simp) (λ s m w, by { ext1, simp [←w] }) }
instance
category_theory.equalizer_regular
category_theory.limits.shapes
src/category_theory/limits/shapes/regular_mono.lean
[ "category_theory.limits.shapes.pullbacks", "category_theory.limits.shapes.strong_epi", "category_theory.limits.shapes.equalizers" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
regular_mono.of_is_split_mono (f : X ⟶ Y) [is_split_mono f] : regular_mono f
{ Z := Y, left := 𝟙 Y, right := retraction f ≫ f, w := by tidy, is_limit := is_split_mono_equalizes f }
instance
category_theory.regular_mono.of_is_split_mono
category_theory.limits.shapes
src/category_theory/limits/shapes/regular_mono.lean
[ "category_theory.limits.shapes.pullbacks", "category_theory.limits.shapes.strong_epi", "category_theory.limits.shapes.equalizers" ]
[]
Every split monomorphism is a regular monomorphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
regular_mono.lift' {W : C} (f : X ⟶ Y) [regular_mono f] (k : W ⟶ Y) (h : k ≫ (regular_mono.left : Y ⟶ @regular_mono.Z _ _ _ _ f _) = k ≫ regular_mono.right) : {l : W ⟶ X // l ≫ f = k}
fork.is_limit.lift' regular_mono.is_limit _ h
def
category_theory.regular_mono.lift'
category_theory.limits.shapes
src/category_theory/limits/shapes/regular_mono.lean
[ "category_theory.limits.shapes.pullbacks", "category_theory.limits.shapes.strong_epi", "category_theory.limits.shapes.equalizers" ]
[]
If `f` is a regular mono, then any map `k : W ⟶ Y` equalizing `regular_mono.left` and `regular_mono.right` induces a morphism `l : W ⟶ X` such that `l ≫ f = k`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
regular_of_is_pullback_snd_of_regular {P Q R S : C} {f : P ⟶ Q} {g : P ⟶ R} {h : Q ⟶ S} {k : R ⟶ S} [hr : regular_mono h] (comm : f ≫ h = g ≫ k) (t : is_limit (pullback_cone.mk _ _ comm)) : regular_mono g
{ Z := hr.Z, left := k ≫ hr.left, right := k ≫ hr.right, w := by rw [← reassoc_of comm, ← reassoc_of comm, hr.w], is_limit := begin apply fork.is_limit.mk' _ _, intro s, have l₁ : (fork.ι s ≫ k) ≫ regular_mono.left = (fork.ι s ≫ k) ≫ regular_mono.right, rw [category.assoc, s.condition, categ...
def
category_theory.regular_of_is_pullback_snd_of_regular
category_theory.limits.shapes
src/category_theory/limits/shapes/regular_mono.lean
[ "category_theory.limits.shapes.pullbacks", "category_theory.limits.shapes.strong_epi", "category_theory.limits.shapes.equalizers" ]
[ "comm" ]
The second leg of a pullback cone is a regular monomorphism if the right component is too. See also `pullback.snd_of_mono` for the basic monomorphism version, and `regular_of_is_pullback_fst_of_regular` for the flipped version.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
regular_of_is_pullback_fst_of_regular {P Q R S : C} {f : P ⟶ Q} {g : P ⟶ R} {h : Q ⟶ S} {k : R ⟶ S} [hr : regular_mono k] (comm : f ≫ h = g ≫ k) (t : is_limit (pullback_cone.mk _ _ comm)) : regular_mono f
regular_of_is_pullback_snd_of_regular comm.symm (pullback_cone.flip_is_limit t)
def
category_theory.regular_of_is_pullback_fst_of_regular
category_theory.limits.shapes
src/category_theory/limits/shapes/regular_mono.lean
[ "category_theory.limits.shapes.pullbacks", "category_theory.limits.shapes.strong_epi", "category_theory.limits.shapes.equalizers" ]
[ "comm" ]
The first leg of a pullback cone is a regular monomorphism if the left component is too. See also `pullback.fst_of_mono` for the basic monomorphism version, and `regular_of_is_pullback_snd_of_regular` for the flipped version.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83