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is_limit_map_cone_empty_cone_equiv : is_limit (G.map_cone (as_empty_cone X)) ≃ is_terminal (G.obj X)
is_limit_empty_cone_equiv D _ _ (eq_to_iso rfl)
def
category_theory.limits.is_limit_map_cone_empty_cone_equiv
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
The map of an empty cone is a limit iff the mapped object is terminal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_terminal.is_terminal_obj [preserves_limit (functor.empty.{0} C) G] (l : is_terminal X) : is_terminal (G.obj X)
is_limit_map_cone_empty_cone_equiv G X (preserves_limit.preserves l)
def
category_theory.limits.is_terminal.is_terminal_obj
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
The property of preserving terminal objects expressed in terms of `is_terminal`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_terminal.is_terminal_of_obj [reflects_limit (functor.empty.{0} C) G] (l : is_terminal (G.obj X)) : is_terminal X
reflects_limit.reflects ((is_limit_map_cone_empty_cone_equiv G X).symm l)
def
category_theory.limits.is_terminal.is_terminal_of_obj
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
The property of reflecting terminal objects expressed in terms of `is_terminal`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_limits_of_shape_pempty_of_preserves_terminal [preserves_limit (functor.empty.{0} C) G] : preserves_limits_of_shape (discrete pempty) G
{ preserves_limit := λ K, preserves_limit_of_iso_diagram G (functor.empty_ext (functor.empty.{0} C) _) }
def
category_theory.limits.preserves_limits_of_shape_pempty_of_preserves_terminal
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[ "pempty" ]
Preserving the terminal object implies preserving all limits of the empty diagram.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_limit_of_has_terminal_of_preserves_limit [preserves_limit (functor.empty.{0} C) G] : is_terminal (G.obj (⊤_ C))
terminal_is_terminal.is_terminal_obj G (⊤_ C)
def
category_theory.limits.is_limit_of_has_terminal_of_preserves_limit
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
If `G` preserves the terminal object and `C` has a terminal object, then the image of the terminal object is terminal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_terminal_of_has_terminal_of_preserves_limit [preserves_limit (functor.empty.{0} C) G] : has_terminal D
⟨λ F, begin haveI := has_limit.mk ⟨_, is_limit_of_has_terminal_of_preserves_limit G⟩, apply has_limit_of_iso F.unique_from_empty.symm, end⟩
lemma
category_theory.limits.has_terminal_of_has_terminal_of_preserves_limit
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
If `C` has a terminal object and `G` preserves terminal objects, then `D` has a terminal object also. Note this property is somewhat unique to (co)limits of the empty diagram: for general `J`, if `C` has limits of shape `J` and `G` preserves them, then `D` does not necessarily have limits of shape `J`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_terminal.of_iso_comparison [i : is_iso (terminal_comparison G)] : preserves_limit (functor.empty C) G
begin apply preserves_limit_of_preserves_limit_cone terminal_is_terminal, apply (is_limit_map_cone_empty_cone_equiv _ _).symm _, apply is_limit.of_point_iso (limit.is_limit (functor.empty.{0} D)), apply i, end
def
category_theory.limits.preserves_terminal.of_iso_comparison
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
If the terminal comparison map for `G` is an isomorphism, then `G` preserves terminal objects.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_terminal_of_is_iso (f : G.obj (⊤_ C) ⟶ ⊤_ D) [i : is_iso f] : preserves_limit (functor.empty C) G
begin rw subsingleton.elim f (terminal_comparison G) at i, exactI preserves_terminal.of_iso_comparison G, end
def
category_theory.limits.preserves_terminal_of_is_iso
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
If there is any isomorphism `G.obj ⊤ ⟶ ⊤`, then `G` preserves terminal objects.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_terminal_of_iso (f : G.obj (⊤_ C) ≅ ⊤_ D) : preserves_limit (functor.empty C) G
preserves_terminal_of_is_iso G f.hom
def
category_theory.limits.preserves_terminal_of_iso
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
If there is any isomorphism `G.obj ⊤ ≅ ⊤`, then `G` preserves terminal objects.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_terminal.iso : G.obj (⊤_ C) ≅ ⊤_ D
(is_limit_of_has_terminal_of_preserves_limit G).cone_point_unique_up_to_iso (limit.is_limit _)
def
category_theory.limits.preserves_terminal.iso
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
If `G` preserves terminal objects, then the terminal comparison map for `G` is an isomorphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_terminal.iso_hom : (preserves_terminal.iso G).hom = terminal_comparison G
rfl
lemma
category_theory.limits.preserves_terminal.iso_hom
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_colimit_map_cocone_empty_cocone_equiv : is_colimit (G.map_cocone (as_empty_cocone.{v₁} X)) ≃ is_initial (G.obj X)
is_colimit_empty_cocone_equiv D _ _ (eq_to_iso rfl)
def
category_theory.limits.is_colimit_map_cocone_empty_cocone_equiv
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
The map of an empty cocone is a colimit iff the mapped object is initial.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_initial.is_initial_obj [preserves_colimit (functor.empty.{0} C) G] (l : is_initial X) : is_initial (G.obj X)
is_colimit_map_cocone_empty_cocone_equiv G X (preserves_colimit.preserves l)
def
category_theory.limits.is_initial.is_initial_obj
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
The property of preserving initial objects expressed in terms of `is_initial`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_initial.is_initial_of_obj [reflects_colimit (functor.empty.{0} C) G] (l : is_initial (G.obj X)) : is_initial X
reflects_colimit.reflects ((is_colimit_map_cocone_empty_cocone_equiv G X).symm l)
def
category_theory.limits.is_initial.is_initial_of_obj
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
The property of reflecting initial objects expressed in terms of `is_initial`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_colimits_of_shape_pempty_of_preserves_initial [preserves_colimit (functor.empty.{0} C) G] : preserves_colimits_of_shape (discrete pempty) G
{ preserves_colimit := λ K, preserves_colimit_of_iso_diagram G (functor.empty_ext (functor.empty.{0} C) _) }
def
category_theory.limits.preserves_colimits_of_shape_pempty_of_preserves_initial
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[ "pempty" ]
Preserving the initial object implies preserving all colimits of the empty diagram.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_colimit_of_has_initial_of_preserves_colimit [preserves_colimit (functor.empty.{0} C) G] : is_initial (G.obj (⊥_ C))
initial_is_initial.is_initial_obj G (⊥_ C)
def
category_theory.limits.is_colimit_of_has_initial_of_preserves_colimit
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
If `G` preserves the initial object and `C` has a initial object, then the image of the initial object is initial.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_initial_of_has_initial_of_preserves_colimit [preserves_colimit (functor.empty.{0} C) G] : has_initial D
⟨λ F, begin haveI := has_colimit.mk ⟨_, is_colimit_of_has_initial_of_preserves_colimit G⟩, apply has_colimit_of_iso F.unique_from_empty, end⟩
lemma
category_theory.limits.has_initial_of_has_initial_of_preserves_colimit
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
If `C` has a initial object and `G` preserves initial objects, then `D` has a initial object also. Note this property is somewhat unique to colimits of the empty diagram: for general `J`, if `C` has colimits of shape `J` and `G` preserves them, then `D` does not necessarily have colimits of shape `J`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_initial.of_iso_comparison [i : is_iso (initial_comparison G)] : preserves_colimit (functor.empty C) G
begin apply preserves_colimit_of_preserves_colimit_cocone initial_is_initial, apply (is_colimit_map_cocone_empty_cocone_equiv _ _).symm _, apply is_colimit.of_point_iso (colimit.is_colimit (functor.empty.{0} D)), apply i, end
def
category_theory.limits.preserves_initial.of_iso_comparison
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
If the initial comparison map for `G` is an isomorphism, then `G` preserves initial objects.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_initial_of_is_iso (f : ⊥_ D ⟶ G.obj (⊥_ C)) [i : is_iso f] : preserves_colimit (functor.empty C) G
begin rw subsingleton.elim f (initial_comparison G) at i, exactI preserves_initial.of_iso_comparison G, end
def
category_theory.limits.preserves_initial_of_is_iso
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
If there is any isomorphism `⊥ ⟶ G.obj ⊥`, then `G` preserves initial objects.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_initial_of_iso (f : ⊥_ D ≅ G.obj (⊥_ C)) : preserves_colimit (functor.empty C) G
preserves_initial_of_is_iso G f.hom
def
category_theory.limits.preserves_initial_of_iso
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
If there is any isomorphism `⊥ ≅ G.obj ⊥ `, then `G` preserves initial objects.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_initial.iso : G.obj (⊥_ C) ≅ ⊥_ D
(is_colimit_of_has_initial_of_preserves_colimit G).cocone_point_unique_up_to_iso (colimit.is_colimit _)
def
category_theory.limits.preserves_initial.iso
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
If `G` preserves initial objects, then the initial comparison map for `G` is an isomorphism.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_initial.iso_hom : (preserves_initial.iso G).inv = initial_comparison G
rfl
lemma
category_theory.limits.preserves_initial.iso_hom
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/terminal.lean
[ "category_theory.limits.shapes.terminal", "category_theory.limits.preserves.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_zero_morphisms (F : C ⥤ D) : Prop
(map_zero' : ∀ (X Y : C), F.map (0 : X ⟶ Y) = 0 . obviously)
class
category_theory.functor.preserves_zero_morphisms
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/zero.lean
[ "category_theory.limits.preserves.shapes.terminal", "category_theory.limits.shapes.zero_morphisms" ]
[]
A functor preserves zero morphisms if it sends zero morphisms to zero morphisms.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_zero (F : C ⥤ D) [preserves_zero_morphisms F] (X Y : C) : F.map (0 : X ⟶ Y) = 0
preserves_zero_morphisms.map_zero' _ _
lemma
category_theory.functor.map_zero
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/zero.lean
[ "category_theory.limits.preserves.shapes.terminal", "category_theory.limits.shapes.zero_morphisms" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
zero_of_map_zero (F : C ⥤ D) [preserves_zero_morphisms F] [faithful F] {X Y : C} (f : X ⟶ Y) (h : F.map f = 0) : f = 0
F.map_injective $ h.trans $ eq.symm $ F.map_zero _ _
lemma
category_theory.functor.zero_of_map_zero
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/zero.lean
[ "category_theory.limits.preserves.shapes.terminal", "category_theory.limits.shapes.zero_morphisms" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_eq_zero_iff (F : C ⥤ D) [preserves_zero_morphisms F] [faithful F] {X Y : C} {f : X ⟶ Y} : F.map f = 0 ↔ f = 0
⟨F.zero_of_map_zero _, by { rintro rfl, exact F.map_zero _ _ }⟩
lemma
category_theory.functor.map_eq_zero_iff
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/zero.lean
[ "category_theory.limits.preserves.shapes.terminal", "category_theory.limits.shapes.zero_morphisms" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_zero_morphisms_of_is_left_adjoint (F : C ⥤ D) [is_left_adjoint F] : preserves_zero_morphisms F
{ map_zero' := λ X Y, let adj := adjunction.of_left_adjoint F in begin calc F.map (0 : X ⟶ Y) = F.map 0 ≫ F.map (adj.unit.app Y) ≫ adj.counit.app (F.obj Y) : _ ... = F.map 0 ≫ F.map ((right_adjoint F).map (0 : F.obj X ⟶ _)) ≫ adj.counit.app (F.obj Y) : _ ... = 0 : _, { rw adjunction.left_triangle_comp...
instance
category_theory.functor.preserves_zero_morphisms_of_is_left_adjoint
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/zero.lean
[ "category_theory.limits.preserves.shapes.terminal", "category_theory.limits.shapes.zero_morphisms" ]
[ "adj" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_zero_morphisms_of_is_right_adjoint (G : C ⥤ D) [is_right_adjoint G] : preserves_zero_morphisms G
{ map_zero' := λ X Y, let adj := adjunction.of_right_adjoint G in begin calc G.map (0 : X ⟶ Y) = adj.unit.app (G.obj X) ≫ G.map (adj.counit.app X) ≫ G.map 0 : _ ... = adj.unit.app (G.obj X) ≫ G.map ((left_adjoint G).map (0 : _ ⟶ G.obj X)) ≫ G.map 0 : _ ... = 0 : _, { rw adjunction.right_triangle_compo...
instance
category_theory.functor.preserves_zero_morphisms_of_is_right_adjoint
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/zero.lean
[ "category_theory.limits.preserves.shapes.terminal", "category_theory.limits.shapes.zero_morphisms" ]
[ "adj" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_zero_morphisms_of_full (F : C ⥤ D) [full F] : preserves_zero_morphisms F
{ map_zero' := λ X Y, calc F.map (0 : X ⟶ Y) = F.map (0 ≫ (F.preimage (0 : F.obj Y ⟶ F.obj Y))) : by rw zero_comp ... = 0 : by rw [F.map_comp, F.image_preimage, comp_zero] }
instance
category_theory.functor.preserves_zero_morphisms_of_full
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/zero.lean
[ "category_theory.limits.preserves.shapes.terminal", "category_theory.limits.shapes.zero_morphisms" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_zero_object [preserves_zero_morphisms F] : F.obj 0 ≅ 0
{ hom := 0, inv := 0, hom_inv_id' := by rw [← F.map_id, id_zero, F.map_zero, zero_comp], inv_hom_id' := by rw [id_zero, comp_zero] }
def
category_theory.functor.map_zero_object
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/zero.lean
[ "category_theory.limits.preserves.shapes.terminal", "category_theory.limits.shapes.zero_morphisms" ]
[]
A functor that preserves zero morphisms also preserves the zero object.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_zero_morphisms_of_map_zero_object (i : F.obj 0 ≅ 0) : preserves_zero_morphisms F
{ map_zero' := λ X Y, calc F.map (0 : X ⟶ Y) = F.map (0 : X ⟶ 0) ≫ F.map 0 : by rw [← functor.map_comp, comp_zero] ... = F.map 0 ≫ (i.hom ≫ i.inv) ≫ F.map 0 : by rw [iso.hom_inv_id, category.id_comp] ... = 0 : by simp only [zero_of_to_zero i.hom, zero_comp, comp...
lemma
category_theory.functor.preserves_zero_morphisms_of_map_zero_object
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/zero.lean
[ "category_theory.limits.preserves.shapes.terminal", "category_theory.limits.shapes.zero_morphisms" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_zero_morphisms_of_preserves_initial_object [preserves_colimit (functor.empty.{0} C) F] : preserves_zero_morphisms F
preserves_zero_morphisms_of_map_zero_object $ F.map_iso has_zero_object.zero_iso_initial ≪≫ preserves_initial.iso F ≪≫ has_zero_object.zero_iso_initial.symm
instance
category_theory.functor.preserves_zero_morphisms_of_preserves_initial_object
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/zero.lean
[ "category_theory.limits.preserves.shapes.terminal", "category_theory.limits.shapes.zero_morphisms" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_zero_morphisms_of_preserves_terminal_object [preserves_limit (functor.empty.{0} C) F] : preserves_zero_morphisms F
preserves_zero_morphisms_of_map_zero_object $ F.map_iso has_zero_object.zero_iso_terminal ≪≫ preserves_terminal.iso F ≪≫ has_zero_object.zero_iso_terminal.symm
instance
category_theory.functor.preserves_zero_morphisms_of_preserves_terminal_object
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/zero.lean
[ "category_theory.limits.preserves.shapes.terminal", "category_theory.limits.shapes.zero_morphisms" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_terminal_object_of_preserves_zero_morphisms [preserves_zero_morphisms F] : preserves_limit (functor.empty C) F
preserves_terminal_of_iso F $ F.map_iso has_zero_object.zero_iso_terminal.symm ≪≫ map_zero_object F ≪≫ has_zero_object.zero_iso_terminal
def
category_theory.functor.preserves_terminal_object_of_preserves_zero_morphisms
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/zero.lean
[ "category_theory.limits.preserves.shapes.terminal", "category_theory.limits.shapes.zero_morphisms" ]
[]
Preserving zero morphisms implies preserving terminal objects.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
preserves_initial_object_of_preserves_zero_morphisms [preserves_zero_morphisms F] : preserves_colimit (functor.empty C) F
preserves_initial_of_iso F $ has_zero_object.zero_iso_initial.symm ≪≫ (map_zero_object F).symm ≪≫ (F.map_iso has_zero_object.zero_iso_initial.symm).symm
def
category_theory.functor.preserves_initial_object_of_preserves_zero_morphisms
category_theory.limits.preserves.shapes
src/category_theory/limits/preserves/shapes/zero.lean
[ "category_theory.limits.preserves.shapes.terminal", "category_theory.limits.shapes.zero_morphisms" ]
[]
Preserving zero morphisms implies preserving terminal objects.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_pair : Type | left | right
inductive
category_theory.limits.walking_pair
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
The type of objects for the diagram indexing a binary (co)product.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_pair.swap : walking_pair ≃ walking_pair
{ to_fun := λ j, walking_pair.rec_on j right left, inv_fun := λ j, walking_pair.rec_on j right left, left_inv := λ j, by { cases j; refl, }, right_inv := λ j, by { cases j; refl, }, }
def
category_theory.limits.walking_pair.swap
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[ "inv_fun" ]
The equivalence swapping left and right.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_pair.swap_apply_left : walking_pair.swap left = right
rfl
lemma
category_theory.limits.walking_pair.swap_apply_left
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_pair.swap_apply_right : walking_pair.swap right = left
rfl
lemma
category_theory.limits.walking_pair.swap_apply_right
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_pair.swap_symm_apply_tt : walking_pair.swap.symm left = right
rfl
lemma
category_theory.limits.walking_pair.swap_symm_apply_tt
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_pair.swap_symm_apply_ff : walking_pair.swap.symm right = left
rfl
lemma
category_theory.limits.walking_pair.swap_symm_apply_ff
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_pair.equiv_bool : walking_pair ≃ bool
{ to_fun := λ j, walking_pair.rec_on j tt ff, -- to match equiv.sum_equiv_sigma_bool inv_fun := λ b, bool.rec_on b right left, left_inv := λ j, by { cases j; refl, }, right_inv := λ b, by { cases b; refl, }, }
def
category_theory.limits.walking_pair.equiv_bool
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[ "inv_fun" ]
An equivalence from `walking_pair` to `bool`, sometimes useful when reindexing limits.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_pair.equiv_bool_apply_left : walking_pair.equiv_bool left = tt
rfl
lemma
category_theory.limits.walking_pair.equiv_bool_apply_left
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_pair.equiv_bool_apply_right : walking_pair.equiv_bool right = ff
rfl
lemma
category_theory.limits.walking_pair.equiv_bool_apply_right
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_pair.equiv_bool_symm_apply_tt : walking_pair.equiv_bool.symm tt = left
rfl
lemma
category_theory.limits.walking_pair.equiv_bool_symm_apply_tt
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
walking_pair.equiv_bool_symm_apply_ff : walking_pair.equiv_bool.symm ff = right
rfl
lemma
category_theory.limits.walking_pair.equiv_bool_symm_apply_ff
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pair_function (X Y : C) : walking_pair → C
λ j, walking_pair.cases_on j X Y
def
category_theory.limits.pair_function
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
The function on the walking pair, sending the two points to `X` and `Y`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pair_function_left (X Y : C) : pair_function X Y left = X
rfl
lemma
category_theory.limits.pair_function_left
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pair_function_right (X Y : C) : pair_function X Y right = Y
rfl
lemma
category_theory.limits.pair_function_right
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pair (X Y : C) : discrete walking_pair ⥤ C
discrete.functor (λ j, walking_pair.cases_on j X Y)
def
category_theory.limits.pair
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
The diagram on the walking pair, sending the two points to `X` and `Y`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pair_obj_left (X Y : C) : (pair X Y).obj ⟨left⟩ = X
rfl
lemma
category_theory.limits.pair_obj_left
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pair_obj_right (X Y : C) : (pair X Y).obj ⟨right⟩ = Y
rfl
lemma
category_theory.limits.pair_obj_right
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_pair : F ⟶ G
{ app := λ j, discrete.rec_on j (λ j, walking_pair.cases_on j f g) }
def
category_theory.limits.map_pair
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
The natural transformation between two functors out of the walking pair, specified by its components.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_pair_left : (map_pair f g).app ⟨left⟩ = f
rfl
lemma
category_theory.limits.map_pair_left
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_pair_right : (map_pair f g).app ⟨right⟩ = g
rfl
lemma
category_theory.limits.map_pair_right
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_pair_iso (f : F.obj ⟨left⟩ ≅ G.obj ⟨left⟩) (g : F.obj ⟨right⟩ ≅ G.obj ⟨right⟩) : F ≅ G
nat_iso.of_components (λ j, discrete.rec_on j (λ j, walking_pair.cases_on j f g)) (by tidy)
def
category_theory.limits.map_pair_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
The natural isomorphism between two functors out of the walking pair, specified by its components.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
diagram_iso_pair (F : discrete walking_pair ⥤ C) : F ≅ pair (F.obj ⟨walking_pair.left⟩) (F.obj ⟨walking_pair.right⟩)
map_pair_iso (iso.refl _) (iso.refl _)
def
category_theory.limits.diagram_iso_pair
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
Every functor out of the walking pair is naturally isomorphic (actually, equal) to a `pair`
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pair_comp (X Y : C) (F : C ⥤ D) : pair X Y ⋙ F ≅ pair (F.obj X) (F.obj Y)
diagram_iso_pair _
def
category_theory.limits.pair_comp
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
The natural isomorphism between `pair X Y ⋙ F` and `pair (F.obj X) (F.obj Y)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_fan (X Y : C)
cone (pair X Y)
abbreviation
category_theory.limits.binary_fan
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
A binary fan is just a cone on a diagram indexing a product.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_fan.fst {X Y : C} (s : binary_fan X Y)
s.π.app ⟨walking_pair.left⟩
abbreviation
category_theory.limits.binary_fan.fst
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
The first projection of a binary fan.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_fan.snd {X Y : C} (s : binary_fan X Y)
s.π.app ⟨walking_pair.right⟩
abbreviation
category_theory.limits.binary_fan.snd
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
The second projection of a binary fan.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_fan.π_app_left {X Y : C} (s : binary_fan X Y) : s.π.app ⟨walking_pair.left⟩ = s.fst
rfl
lemma
category_theory.limits.binary_fan.π_app_left
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_fan.π_app_right {X Y : C} (s : binary_fan X Y) : s.π.app ⟨walking_pair.right⟩ = s.snd
rfl
lemma
category_theory.limits.binary_fan.π_app_right
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_fan.is_limit.mk {X Y : C} (s : binary_fan X Y) (lift : Π {T : C} (f : T ⟶ X) (g : T ⟶ Y), T ⟶ s.X) (hl₁ : ∀ {T : C} (f : T ⟶ X) (g : T ⟶ Y), lift f g ≫ s.fst = f) (hl₂ : ∀ {T : C} (f : T ⟶ X) (g : T ⟶ Y), lift f g ≫ s.snd = g) (uniq : ∀ {T : C} (f : T ⟶ X) (g : T ⟶ Y) (m : T ⟶ s.X) (h₁ : m ≫ s.fst = f) ...
is_limit.mk (λ t, lift (binary_fan.fst t) (binary_fan.snd t)) (by { rintros t (rfl|rfl), { exact hl₁ _ _ }, { exact hl₂ _ _ } }) (λ t m h, uniq _ _ _ (h ⟨walking_pair.left⟩) (h ⟨walking_pair.right⟩))
def
category_theory.limits.binary_fan.is_limit.mk
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[ "lift" ]
A convenient way to show that a binary fan is a limit.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_fan.is_limit.hom_ext {W X Y : C} {s : binary_fan X Y} (h : is_limit s) {f g : W ⟶ s.X} (h₁ : f ≫ s.fst = g ≫ s.fst) (h₂ : f ≫ s.snd = g ≫ s.snd) : f = g
h.hom_ext $ λ j, discrete.rec_on j (λ j, walking_pair.cases_on j h₁ h₂)
lemma
category_theory.limits.binary_fan.is_limit.hom_ext
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_cofan (X Y : C)
cocone (pair X Y)
abbreviation
category_theory.limits.binary_cofan
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
A binary cofan is just a cocone on a diagram indexing a coproduct.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_cofan.inl {X Y : C} (s : binary_cofan X Y)
s.ι.app ⟨walking_pair.left⟩
abbreviation
category_theory.limits.binary_cofan.inl
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
The first inclusion of a binary cofan.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_cofan.inr {X Y : C} (s : binary_cofan X Y)
s.ι.app ⟨walking_pair.right⟩
abbreviation
category_theory.limits.binary_cofan.inr
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
The second inclusion of a binary cofan.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_cofan.ι_app_left {X Y : C} (s : binary_cofan X Y) : s.ι.app ⟨walking_pair.left⟩ = s.inl
rfl
lemma
category_theory.limits.binary_cofan.ι_app_left
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_cofan.ι_app_right {X Y : C} (s : binary_cofan X Y) : s.ι.app ⟨walking_pair.right⟩ = s.inr
rfl
lemma
category_theory.limits.binary_cofan.ι_app_right
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_cofan.is_colimit.mk {X Y : C} (s : binary_cofan X Y) (desc : Π {T : C} (f : X ⟶ T) (g : Y ⟶ T), s.X ⟶ T) (hd₁ : ∀ {T : C} (f : X ⟶ T) (g : Y ⟶ T), s.inl ≫ desc f g = f) (hd₂ : ∀ {T : C} (f : X ⟶ T) (g : Y ⟶ T), s.inr ≫ desc f g = g) (uniq : ∀ {T : C} (f : X ⟶ T) (g : Y ⟶ T) (m : s.X ⟶ T) (h₁ : s.inl ≫ m ...
is_colimit.mk (λ t, desc (binary_cofan.inl t) (binary_cofan.inr t)) (by { rintros t (rfl|rfl), { exact hd₁ _ _ }, { exact hd₂ _ _ }}) (λ t m h, uniq _ _ _ (h ⟨walking_pair.left⟩) (h ⟨walking_pair.right⟩))
def
category_theory.limits.binary_cofan.is_colimit.mk
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
A convenient way to show that a binary cofan is a colimit.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_cofan.is_colimit.hom_ext {W X Y : C} {s : binary_cofan X Y} (h : is_colimit s) {f g : s.X ⟶ W} (h₁ : s.inl ≫ f = s.inl ≫ g) (h₂ : s.inr ≫ f = s.inr ≫ g) : f = g
h.hom_ext $ λ j, discrete.rec_on j (λ j, walking_pair.cases_on j h₁ h₂)
lemma
category_theory.limits.binary_cofan.is_colimit.hom_ext
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_fan.mk {P : C} (π₁ : P ⟶ X) (π₂ : P ⟶ Y) : binary_fan X Y
{ X := P, π := { app := λ j, discrete.rec_on j (λ j, walking_pair.cases_on j π₁ π₂) }}
def
category_theory.limits.binary_fan.mk
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
A binary fan with vertex `P` consists of the two projections `π₁ : P ⟶ X` and `π₂ : P ⟶ Y`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_cofan.mk {P : C} (ι₁ : X ⟶ P) (ι₂ : Y ⟶ P) : binary_cofan X Y
{ X := P, ι := { app := λ j, discrete.rec_on j (λ j, walking_pair.cases_on j ι₁ ι₂) }}
def
category_theory.limits.binary_cofan.mk
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
A binary cofan with vertex `P` consists of the two inclusions `ι₁ : X ⟶ P` and `ι₂ : Y ⟶ P`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_fan.mk_fst {P : C} (π₁ : P ⟶ X) (π₂ : P ⟶ Y) : (binary_fan.mk π₁ π₂).fst = π₁
rfl
lemma
category_theory.limits.binary_fan.mk_fst
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_fan.mk_snd {P : C} (π₁ : P ⟶ X) (π₂ : P ⟶ Y) : (binary_fan.mk π₁ π₂).snd = π₂
rfl
lemma
category_theory.limits.binary_fan.mk_snd
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_cofan.mk_inl {P : C} (ι₁ : X ⟶ P) (ι₂ : Y ⟶ P) : (binary_cofan.mk ι₁ ι₂).inl = ι₁
rfl
lemma
category_theory.limits.binary_cofan.mk_inl
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_cofan.mk_inr {P : C} (ι₁ : X ⟶ P) (ι₂ : Y ⟶ P) : (binary_cofan.mk ι₁ ι₂).inr = ι₂
rfl
lemma
category_theory.limits.binary_cofan.mk_inr
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iso_binary_fan_mk {X Y : C} (c : binary_fan X Y) : c ≅ binary_fan.mk c.fst c.snd
cones.ext (iso.refl _) (λ j, by discrete_cases; cases j; tidy)
def
category_theory.limits.iso_binary_fan_mk
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
Every `binary_fan` is isomorphic to an application of `binary_fan.mk`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iso_binary_cofan_mk {X Y : C} (c : binary_cofan X Y) : c ≅ binary_cofan.mk c.inl c.inr
cocones.ext (iso.refl _) (λ j, by discrete_cases; cases j; tidy)
def
category_theory.limits.iso_binary_cofan_mk
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
Every `binary_fan` is isomorphic to an application of `binary_fan.mk`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_fan.is_limit_mk {W : C} {fst : W ⟶ X} {snd : W ⟶ Y} (lift : Π (s : binary_fan X Y), s.X ⟶ W) (fac_left : ∀ (s : binary_fan X Y), lift s ≫ fst = s.fst) (fac_right : ∀ (s : binary_fan X Y), lift s ≫ snd = s.snd) (uniq : ∀ (s : binary_fan X Y) (m : s.X ⟶ W) (w_fst : m ≫ fst = s.fst) (w_snd : m ≫ snd = s...
{ lift := lift, fac' := λ s j, by { rcases j with ⟨⟨⟩⟩, exacts [fac_left s, fac_right s], }, uniq' := λ s m w, uniq s m (w ⟨walking_pair.left⟩) (w ⟨walking_pair.right⟩) }
def
category_theory.limits.binary_fan.is_limit_mk
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[ "lift" ]
This is a more convenient formulation to show that a `binary_fan` constructed using `binary_fan.mk` is a limit cone.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_cofan.is_colimit_mk {W : C} {inl : X ⟶ W} {inr : Y ⟶ W} (desc : Π (s : binary_cofan X Y), W ⟶ s.X) (fac_left : ∀ (s : binary_cofan X Y), inl ≫ desc s = s.inl) (fac_right : ∀ (s : binary_cofan X Y), inr ≫ desc s = s.inr) (uniq : ∀ (s : binary_cofan X Y) (m : W ⟶ s.X) (w_inl : inl ≫ m = s.inl) (w_inr :...
{ desc := desc, fac' := λ s j, by { rcases j with ⟨⟨⟩⟩, exacts [fac_left s, fac_right s], }, uniq' := λ s m w, uniq s m (w ⟨walking_pair.left⟩) (w ⟨walking_pair.right⟩) }
def
category_theory.limits.binary_cofan.is_colimit_mk
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
This is a more convenient formulation to show that a `binary_cofan` constructed using `binary_cofan.mk` is a colimit cocone.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_fan.is_limit.lift' {W X Y : C} {s : binary_fan X Y} (h : is_limit s) (f : W ⟶ X) (g : W ⟶ Y) : {l : W ⟶ s.X // l ≫ s.fst = f ∧ l ≫ s.snd = g}
⟨h.lift $ binary_fan.mk f g, h.fac _ _, h.fac _ _⟩
def
category_theory.limits.binary_fan.is_limit.lift'
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
If `s` is a limit binary fan over `X` and `Y`, then every pair of morphisms `f : W ⟶ X` and `g : W ⟶ Y` induces a morphism `l : W ⟶ s.X` satisfying `l ≫ s.fst = f` and `l ≫ s.snd = g`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_cofan.is_colimit.desc' {W X Y : C} {s : binary_cofan X Y} (h : is_colimit s) (f : X ⟶ W) (g : Y ⟶ W) : {l : s.X ⟶ W // s.inl ≫ l = f ∧ s.inr ≫ l = g}
⟨h.desc $ binary_cofan.mk f g, h.fac _ _, h.fac _ _⟩
def
category_theory.limits.binary_cofan.is_colimit.desc'
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
If `s` is a colimit binary cofan over `X` and `Y`,, then every pair of morphisms `f : X ⟶ W` and `g : Y ⟶ W` induces a morphism `l : s.X ⟶ W` satisfying `s.inl ≫ l = f` and `s.inr ≫ l = g`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_fan.is_limit_flip {X Y : C} {c : binary_fan X Y} (hc : is_limit c) : is_limit (binary_fan.mk c.snd c.fst)
binary_fan.is_limit_mk (λ s, hc.lift (binary_fan.mk s.snd s.fst)) (λ s, hc.fac _ _) (λ s, hc.fac _ _) (λ s m e₁ e₂, binary_fan.is_limit.hom_ext hc (e₂.trans (hc.fac (binary_fan.mk s.snd s.fst) ⟨walking_pair.left⟩).symm) (e₁.trans (hc.fac (binary_fan.mk s.snd s.fst) ⟨walking_pair.right⟩).symm))
def
category_theory.limits.binary_fan.is_limit_flip
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
Binary products are symmetric.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_fan.is_limit_iff_is_iso_fst {X Y : C} (h : is_terminal Y) (c : binary_fan X Y) : nonempty (is_limit c) ↔ is_iso c.fst
begin split, { rintro ⟨H⟩, obtain ⟨l, hl, -⟩ := binary_fan.is_limit.lift' H (𝟙 X) (h.from X), exact ⟨⟨l, binary_fan.is_limit.hom_ext H (by simpa [hl, -category.comp_id] using category.comp_id _) (h.hom_ext _ _), hl⟩⟩ }, { introI, exact ⟨binary_fan.is_limit.mk _ (λ _ f _, f ≫ inv c.fst) (λ...
lemma
category_theory.limits.binary_fan.is_limit_iff_is_iso_fst
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_fan.is_limit_iff_is_iso_snd {X Y : C} (h : is_terminal X) (c : binary_fan X Y) : nonempty (is_limit c) ↔ is_iso c.snd
begin refine iff.trans _ (binary_fan.is_limit_iff_is_iso_fst h (binary_fan.mk c.snd c.fst)), exact ⟨λ h, ⟨binary_fan.is_limit_flip h.some⟩, λ h, ⟨(binary_fan.is_limit_flip h.some).of_iso_limit (iso_binary_fan_mk c).symm⟩⟩, end
lemma
category_theory.limits.binary_fan.is_limit_iff_is_iso_snd
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_fan.is_limit_comp_left_iso {X Y X' : C} (c : binary_fan X Y) (f : X ⟶ X') [is_iso f] (h : is_limit c) : is_limit (binary_fan.mk (c.fst ≫ f) c.snd)
begin fapply binary_fan.is_limit_mk, { exact λ s, h.lift (binary_fan.mk (s.fst ≫ inv f) s.snd) }, { intro s, simp }, { intro s, simp }, { intros s m e₁ e₂, apply binary_fan.is_limit.hom_ext h; simpa } end
def
category_theory.limits.binary_fan.is_limit_comp_left_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
If `X' ≅ X`, then `X × Y` also is the product of `X'` and `Y`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_fan.is_limit_comp_right_iso {X Y Y' : C} (c : binary_fan X Y) (f : Y ⟶ Y') [is_iso f] (h : is_limit c) : is_limit (binary_fan.mk c.fst (c.snd ≫ f))
binary_fan.is_limit_flip $ binary_fan.is_limit_comp_left_iso _ f (binary_fan.is_limit_flip h)
def
category_theory.limits.binary_fan.is_limit_comp_right_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
If `Y' ≅ Y`, then `X x Y` also is the product of `X` and `Y'`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_cofan.is_colimit_flip {X Y : C} {c : binary_cofan X Y} (hc : is_colimit c) : is_colimit (binary_cofan.mk c.inr c.inl)
binary_cofan.is_colimit_mk (λ s, hc.desc (binary_cofan.mk s.inr s.inl)) (λ s, hc.fac _ _) (λ s, hc.fac _ _) (λ s m e₁ e₂, binary_cofan.is_colimit.hom_ext hc (e₂.trans (hc.fac (binary_cofan.mk s.inr s.inl) ⟨walking_pair.left⟩).symm) (e₁.trans (hc.fac (binary_cofan.mk s.inr s.inl) ⟨walking_pair.right⟩).symm))
def
category_theory.limits.binary_cofan.is_colimit_flip
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
Binary coproducts are symmetric.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_cofan.is_colimit_iff_is_iso_inl {X Y : C} (h : is_initial Y) (c : binary_cofan X Y) : nonempty (is_colimit c) ↔ is_iso c.inl
begin split, { rintro ⟨H⟩, obtain ⟨l, hl, -⟩ := binary_cofan.is_colimit.desc' H (𝟙 X) (h.to X), exact ⟨⟨l, hl, binary_cofan.is_colimit.hom_ext H (by simp [reassoc_of hl]) (h.hom_ext _ _)⟩⟩ }, { introI, exact ⟨binary_cofan.is_colimit.mk _ (λ _ f _, inv c.inl ≫ f) (λ _ _ _, is_iso.hom_inv_id_asso...
lemma
category_theory.limits.binary_cofan.is_colimit_iff_is_iso_inl
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_cofan.is_colimit_iff_is_iso_inr {X Y : C} (h : is_initial X) (c : binary_cofan X Y) : nonempty (is_colimit c) ↔ is_iso c.inr
begin refine iff.trans _ (binary_cofan.is_colimit_iff_is_iso_inl h (binary_cofan.mk c.inr c.inl)), exact ⟨λ h, ⟨binary_cofan.is_colimit_flip h.some⟩, λ h, ⟨(binary_cofan.is_colimit_flip h.some).of_iso_colimit (iso_binary_cofan_mk c).symm⟩⟩, end
lemma
category_theory.limits.binary_cofan.is_colimit_iff_is_iso_inr
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_cofan.is_colimit_comp_left_iso {X Y X' : C} (c : binary_cofan X Y) (f : X' ⟶ X) [is_iso f] (h : is_colimit c) : is_colimit (binary_cofan.mk (f ≫ c.inl) c.inr)
begin fapply binary_cofan.is_colimit_mk, { exact λ s, h.desc (binary_cofan.mk (inv f ≫ s.inl) s.inr) }, { intro s, simp }, { intro s, simp }, { intros s m e₁ e₂, apply binary_cofan.is_colimit.hom_ext h, { rw ← cancel_epi f, simpa using e₁ }, { simpa } } end
def
category_theory.limits.binary_cofan.is_colimit_comp_left_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
If `X' ≅ X`, then `X ⨿ Y` also is the coproduct of `X'` and `Y`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
binary_cofan.is_colimit_comp_right_iso {X Y Y' : C} (c : binary_cofan X Y) (f : Y' ⟶ Y) [is_iso f] (h : is_colimit c) : is_colimit (binary_cofan.mk c.inl (f ≫ c.inr))
binary_cofan.is_colimit_flip $ binary_cofan.is_colimit_comp_left_iso _ f (binary_cofan.is_colimit_flip h)
def
category_theory.limits.binary_cofan.is_colimit_comp_right_iso
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
If `Y' ≅ Y`, then `X ⨿ Y` also is the coproduct of `X` and `Y'`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_binary_product (X Y : C)
has_limit (pair X Y)
abbreviation
category_theory.limits.has_binary_product
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
An abbreviation for `has_limit (pair X Y)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
has_binary_coproduct (X Y : C)
has_colimit (pair X Y)
abbreviation
category_theory.limits.has_binary_coproduct
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
An abbreviation for `has_colimit (pair X Y)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod (X Y : C) [has_binary_product X Y]
limit (pair X Y)
abbreviation
category_theory.limits.prod
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
If we have a product of `X` and `Y`, we can access it using `prod X Y` or `X ⨯ Y`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
coprod (X Y : C) [has_binary_coproduct X Y]
colimit (pair X Y)
abbreviation
category_theory.limits.coprod
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
If we have a coproduct of `X` and `Y`, we can access it using `coprod X Y ` or `X ⨿ Y`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod.fst {X Y : C} [has_binary_product X Y] : X ⨯ Y ⟶ X
limit.π (pair X Y) ⟨walking_pair.left⟩
abbreviation
category_theory.limits.prod.fst
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
The projection map to the first component of the product.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
prod.snd {X Y : C} [has_binary_product X Y] : X ⨯ Y ⟶ Y
limit.π (pair X Y) ⟨walking_pair.right⟩
abbreviation
category_theory.limits.prod.snd
category_theory.limits.shapes
src/category_theory/limits/shapes/binary_products.lean
[ "category_theory.limits.shapes.terminal", "category_theory.discrete_category", "category_theory.epi_mono", "category_theory.over" ]
[]
The projecton map to the second component of the product.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83