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types_hom {α β : Type u} : (α ⟶ β) = (α → β)
rfl
lemma
category_theory.types_hom
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
types_id (X : Type u) : 𝟙 X = id
rfl
lemma
category_theory.types_id
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
types_comp {X Y Z : Type u} (f : X ⟶ Y) (g : Y ⟶ Z) : f ≫ g = g ∘ f
rfl
lemma
category_theory.types_comp
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
types_id_apply (X : Type u) (x : X) : ((𝟙 X) : X → X) x = x
rfl
lemma
category_theory.types_id_apply
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
types_comp_apply {X Y Z : Type u} (f : X ⟶ Y) (g : Y ⟶ Z) (x : X) : (f ≫ g) x = g (f x)
rfl
lemma
category_theory.types_comp_apply
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_inv_id_apply {X Y : Type u} (f : X ≅ Y) (x : X) : f.inv (f.hom x) = x
congr_fun f.hom_inv_id x
lemma
category_theory.hom_inv_id_apply
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv_hom_id_apply {X Y : Type u} (f : X ≅ Y) (y : Y) : f.hom (f.inv y) = y
congr_fun f.inv_hom_id y
lemma
category_theory.inv_hom_id_apply
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
as_hom {α β : Type u} (f : α → β) : α ⟶ β
f
abbreviation
category_theory.as_hom
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
sections (F : J ⥤ Type w) : set (Π j, F.obj j)
{ u | ∀ {j j'} (f : j ⟶ j'), F.map f (u j) = u j'}
def
category_theory.functor.sections
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
The sections of a functor `J ⥤ Type` are the choices of a point `u j : F.obj j` for each `j`, such that `F.map f (u j) = u j` for every morphism `f : j ⟶ j'`. We later use these to define limits in `Type` and in many concrete categories.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_comp_apply (f : X ⟶ Y) (g : Y ⟶ Z) (a : F.obj X) : (F.map (f ≫ g)) a = (F.map g) ((F.map f) a)
by simp [types_comp]
lemma
category_theory.functor_to_types.map_comp_apply
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_id_apply (a : F.obj X) : (F.map (𝟙 X)) a = a
by simp [types_id]
lemma
category_theory.functor_to_types.map_id_apply
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
naturality (f : X ⟶ Y) (x : F.obj X) : σ.app Y ((F.map f) x) = (G.map f) (σ.app X x)
congr_fun (σ.naturality f) x
lemma
category_theory.functor_to_types.naturality
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp (x : F.obj X) : (σ ≫ τ).app X x = τ.app X (σ.app X x)
rfl
lemma
category_theory.functor_to_types.comp
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hcomp (x : (I ⋙ F).obj W) : (ρ ◫ σ).app W x = (G.map (ρ.app W)) (σ.app (I.obj W) x)
rfl
lemma
category_theory.functor_to_types.hcomp
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_inv_map_hom_apply (f : X ≅ Y) (x : F.obj X) : F.map f.inv (F.map f.hom x) = x
congr_fun (F.map_iso f).hom_inv_id x
lemma
category_theory.functor_to_types.map_inv_map_hom_apply
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map_hom_map_inv_apply (f : X ≅ Y) (y : F.obj Y) : F.map f.hom (F.map f.inv y) = y
congr_fun (F.map_iso f).inv_hom_id y
lemma
category_theory.functor_to_types.map_hom_map_inv_apply
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_inv_id_app_apply (α : F ≅ G) (X) (x) : α.inv.app X (α.hom.app X x) = x
congr_fun (α.hom_inv_id_app X) x
lemma
category_theory.functor_to_types.hom_inv_id_app_apply
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
inv_hom_id_app_apply (α : F ≅ G) (X) (x) : α.hom.app X (α.inv.app X x) = x
congr_fun (α.inv_hom_id_app X) x
lemma
category_theory.functor_to_types.inv_hom_id_app_apply
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ulift_trivial (V : Type u) : ulift.{u} V ≅ V
by tidy
def
category_theory.ulift_trivial
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
The isomorphism between a `Type` which has been `ulift`ed to the same universe, and the original type.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ulift_functor : Type u ⥤ Type (max u v)
{ obj := λ X, ulift.{v} X, map := λ X Y f, λ x : ulift.{v} X, ulift.up (f x.down) }
def
category_theory.ulift_functor
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
The functor embedding `Type u` into `Type (max u v)`. Write this as `ulift_functor.{5 2}` to get `Type 2 ⥤ Type 5`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ulift_functor_map {X Y : Type u} (f : X ⟶ Y) (x : ulift.{v} X) : ulift_functor.map f x = ulift.up (f x.down)
rfl
lemma
category_theory.ulift_functor_map
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ulift_functor_full : full.{u} ulift_functor
{ preimage := λ X Y f x, (f (ulift.up x)).down }
instance
category_theory.ulift_functor_full
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ulift_functor_faithful : faithful ulift_functor
{ map_injective' := λ X Y f g p, funext $ λ x, congr_arg ulift.down ((congr_fun p (ulift.up x)) : ((ulift.up (f x)) = (ulift.up (g x)))) }
instance
category_theory.ulift_functor_faithful
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
ulift_functor_trivial : ulift_functor.{u u} ≅ 𝟭 _
nat_iso.of_components ulift_trivial (by tidy)
def
category_theory.ulift_functor_trivial
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
The functor embedding `Type u` into `Type u` via `ulift` is isomorphic to the identity functor.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_of_element {X : Type u} (x : X) : punit ⟶ X
λ _, x
def
category_theory.hom_of_element
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_of_element_eq_iff {X : Type u} (x y : X) : hom_of_element x = hom_of_element y ↔ x = y
⟨λ H, congr_fun H punit.star, by cc⟩
lemma
category_theory.hom_of_element_eq_iff
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
mono_iff_injective {X Y : Type u} (f : X ⟶ Y) : mono f ↔ function.injective f
begin split, { intros H x x' h, resetI, rw ←hom_of_element_eq_iff at ⊢ h, exact (cancel_mono f).mp h }, { exact λ H, ⟨λ Z, H.comp_left⟩ } end
lemma
category_theory.mono_iff_injective
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
A morphism in `Type` is a monomorphism if and only if it is injective. See <https://stacks.math.columbia.edu/tag/003C>.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
injective_of_mono {X Y : Type u} (f : X ⟶ Y) [hf : mono f] : function.injective f
(mono_iff_injective f).1 hf
lemma
category_theory.injective_of_mono
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
epi_iff_surjective {X Y : Type u} (f : X ⟶ Y) : epi f ↔ function.surjective f
begin split, { rintros ⟨H⟩, refine function.surjective_of_right_cancellable_Prop (λ g₁ g₂ hg, _), rw [← equiv.ulift.symm.injective.comp_left.eq_iff], apply H, change ulift.up ∘ (g₁ ∘ f) = ulift.up ∘ (g₂ ∘ f), rw hg }, { exact λ H, ⟨λ Z, H.injective_comp_right⟩ } end
lemma
category_theory.epi_iff_surjective
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[ "function.surjective_of_right_cancellable_Prop" ]
A morphism in `Type` is an epimorphism if and only if it is surjective. See <https://stacks.math.columbia.edu/tag/003C>.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
surjective_of_epi {X Y : Type u} (f : X ⟶ Y) [hf : epi f] : function.surjective f
(epi_iff_surjective f).1 hf
lemma
category_theory.surjective_of_epi
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_type_functor (m : Type u → Type v) [_root_.functor m] [is_lawful_functor m] : Type u ⥤ Type v
{ obj := m, map := λα β, _root_.functor.map, map_id' := assume α, _root_.functor.map_id, map_comp' := assume α β γ f g, funext $ assume a, is_lawful_functor.comp_map f g _ }
def
category_theory.of_type_functor
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
`of_type_functor m` converts from Lean's `Type`-based `category` to `category_theory`. This allows us to use these functors in category theory.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_type_functor_obj : (of_type_functor m).obj = m
rfl
lemma
category_theory.of_type_functor_obj
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
of_type_functor_map {α β} (f : α → β) : (of_type_functor m).map f = (_root_.functor.map f : m α → m β)
rfl
lemma
category_theory.of_type_functor_map
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_iso (e : X ≃ Y) : X ≅ Y
{ hom := e.to_fun, inv := e.inv_fun, hom_inv_id' := funext e.left_inv, inv_hom_id' := funext e.right_inv }
def
equiv.to_iso
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
Any equivalence between types in the same universe gives a categorical isomorphism between those types.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_iso_hom {e : X ≃ Y} : e.to_iso.hom = e
rfl
lemma
equiv.to_iso_hom
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_iso_inv {e : X ≃ Y} : e.to_iso.inv = e.symm
rfl
lemma
equiv.to_iso_inv
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_equiv (i : X ≅ Y) : X ≃ Y
{ to_fun := i.hom, inv_fun := i.inv, left_inv := λ x, congr_fun i.hom_inv_id x, right_inv := λ y, congr_fun i.inv_hom_id y }
def
category_theory.iso.to_equiv
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[ "inv_fun" ]
Any isomorphism between types gives an equivalence.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_equiv_fun (i : X ≅ Y) : (i.to_equiv : X → Y) = i.hom
rfl
lemma
category_theory.iso.to_equiv_fun
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_equiv_symm_fun (i : X ≅ Y) : (i.to_equiv.symm : Y → X) = i.inv
rfl
lemma
category_theory.iso.to_equiv_symm_fun
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_equiv_id (X : Type u) : (iso.refl X).to_equiv = equiv.refl X
rfl
lemma
category_theory.iso.to_equiv_id
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[ "equiv.refl" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
to_equiv_comp {X Y Z : Type u} (f : X ≅ Y) (g : Y ≅ Z) : (f ≪≫ g).to_equiv = f.to_equiv.trans (g.to_equiv)
rfl
lemma
category_theory.iso.to_equiv_comp
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_iso_iff_bijective {X Y : Type u} (f : X ⟶ Y) : is_iso f ↔ function.bijective f
iff.intro (λ i, (by exactI as_iso f : X ≅ Y).to_equiv.bijective) (λ b, is_iso.of_iso (equiv.of_bijective f b).to_iso)
lemma
category_theory.is_iso_iff_bijective
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[ "equiv.of_bijective" ]
A morphism in `Type u` is an isomorphism if and only if it is bijective.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equiv_iso_iso {X Y : Type u} : (X ≃ Y) ≅ (X ≅ Y)
{ hom := λ e, e.to_iso, inv := λ i, i.to_equiv, }
def
equiv_iso_iso
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
Equivalences (between types in the same universe) are the same as (isomorphic to) isomorphisms of types.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equiv_equiv_iso {X Y : Type u} : (X ≃ Y) ≃ (X ≅ Y)
(equiv_iso_iso).to_equiv
def
equiv_equiv_iso
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[ "equiv_iso_iso" ]
Equivalences (between types in the same universe) are the same as (equivalent to) isomorphisms of types.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equiv_equiv_iso_hom {X Y : Type u} (e : X ≃ Y) : equiv_equiv_iso e = e.to_iso
rfl
lemma
equiv_equiv_iso_hom
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[ "equiv_equiv_iso" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
equiv_equiv_iso_inv {X Y : Type u} (e : X ≅ Y) : equiv_equiv_iso.symm e = e.to_equiv
rfl
lemma
equiv_equiv_iso_inv
category_theory
src/category_theory/types.lean
[ "category_theory.epi_mono", "category_theory.functor.fully_faithful", "logic.equiv.basic" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
whisker_left (F : C ⥤ D) {G H : D ⥤ E} (α : G ⟶ H) : (F ⋙ G) ⟶ (F ⋙ H)
{ app := λ X, α.app (F.obj X), naturality' := λ X Y f, by rw [functor.comp_map, functor.comp_map, α.naturality] }
def
category_theory.whisker_left
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
If `α : G ⟶ H` then `whisker_left F α : (F ⋙ G) ⟶ (F ⋙ H)` has components `α.app (F.obj X)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
whisker_right {G H : C ⥤ D} (α : G ⟶ H) (F : D ⥤ E) : (G ⋙ F) ⟶ (H ⋙ F)
{ app := λ X, F.map (α.app X), naturality' := λ X Y f, by rw [functor.comp_map, functor.comp_map, ←F.map_comp, ←F.map_comp, α.naturality] }
def
category_theory.whisker_right
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
If `α : G ⟶ H` then `whisker_right α F : (G ⋙ F) ⟶ (G ⋙ F)` has components `F.map (α.app X)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
whiskering_left : (C ⥤ D) ⥤ ((D ⥤ E) ⥤ (C ⥤ E))
{ obj := λ F, { obj := λ G, F ⋙ G, map := λ G H α, whisker_left F α }, map := λ F G τ, { app := λ H, { app := λ c, H.map (τ.app c), naturality' := λ X Y f, begin dsimp, rw [←H.map_comp, ←H.map_comp, ←τ.naturality] end }, naturality' := λ X Y f, begin ext, dsimp, rw [f.naturality] end } }
def
category_theory.whiskering_left
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
Left-composition gives a functor `(C ⥤ D) ⥤ ((D ⥤ E) ⥤ (C ⥤ E))`. `(whiskering_left.obj F).obj G` is `F ⋙ G`, and `(whiskering_left.obj F).map α` is `whisker_left F α`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
whiskering_right : (D ⥤ E) ⥤ ((C ⥤ D) ⥤ (C ⥤ E))
{ obj := λ H, { obj := λ F, F ⋙ H, map := λ _ _ α, whisker_right α H }, map := λ G H τ, { app := λ F, { app := λ c, τ.app (F.obj c), naturality' := λ X Y f, begin dsimp, rw [τ.naturality] end }, naturality' := λ X Y f, begin ext, dsimp, rw [←nat_trans.naturality] end } }
def
category_theory.whiskering_right
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
Right-composition gives a functor `(D ⥤ E) ⥤ ((C ⥤ D) ⥤ (C ⥤ E))`. `(whiskering_right.obj H).obj F` is `F ⋙ H`, and `(whiskering_right.obj H).map α` is `whisker_right α H`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
faithful_whiskering_right_obj {F : D ⥤ E} [faithful F] : faithful ((whiskering_right C D E).obj F)
{ map_injective' := λ G H α β hαβ, nat_trans.ext _ _ $ funext $ λ X, functor.map_injective _ $ congr_fun (congr_arg nat_trans.app hαβ) X }
instance
category_theory.faithful_whiskering_right_obj
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
whisker_left_id (F : C ⥤ D) {G : D ⥤ E} : whisker_left F (nat_trans.id G) = nat_trans.id (F.comp G)
rfl
lemma
category_theory.whisker_left_id
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
whisker_left_id' (F : C ⥤ D) {G : D ⥤ E} : whisker_left F (𝟙 G) = 𝟙 (F.comp G)
rfl
lemma
category_theory.whisker_left_id'
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
whisker_right_id {G : C ⥤ D} (F : D ⥤ E) : whisker_right (nat_trans.id G) F = nat_trans.id (G.comp F)
((whiskering_right C D E).obj F).map_id _
lemma
category_theory.whisker_right_id
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[ "map_id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
whisker_right_id' {G : C ⥤ D} (F : D ⥤ E) : whisker_right (𝟙 G) F = 𝟙 (G.comp F)
((whiskering_right C D E).obj F).map_id _
lemma
category_theory.whisker_right_id'
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[ "map_id" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
whisker_left_comp (F : C ⥤ D) {G H K : D ⥤ E} (α : G ⟶ H) (β : H ⟶ K) : whisker_left F (α ≫ β) = (whisker_left F α) ≫ (whisker_left F β)
rfl
lemma
category_theory.whisker_left_comp
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
whisker_right_comp {G H K : C ⥤ D} (α : G ⟶ H) (β : H ⟶ K) (F : D ⥤ E) : whisker_right (α ≫ β) F = (whisker_right α F) ≫ (whisker_right β F)
((whiskering_right C D E).obj F).map_comp α β
lemma
category_theory.whisker_right_comp
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[ "map_comp" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iso_whisker_left (F : C ⥤ D) {G H : D ⥤ E} (α : G ≅ H) : (F ⋙ G) ≅ (F ⋙ H)
((whiskering_left C D E).obj F).map_iso α
def
category_theory.iso_whisker_left
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
If `α : G ≅ H` is a natural isomorphism then `iso_whisker_left F α : (F ⋙ G) ≅ (F ⋙ H)` has components `α.app (F.obj X)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iso_whisker_left_hom (F : C ⥤ D) {G H : D ⥤ E} (α : G ≅ H) : (iso_whisker_left F α).hom = whisker_left F α.hom
rfl
lemma
category_theory.iso_whisker_left_hom
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iso_whisker_left_inv (F : C ⥤ D) {G H : D ⥤ E} (α : G ≅ H) : (iso_whisker_left F α).inv = whisker_left F α.inv
rfl
lemma
category_theory.iso_whisker_left_inv
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iso_whisker_right {G H : C ⥤ D} (α : G ≅ H) (F : D ⥤ E) : (G ⋙ F) ≅ (H ⋙ F)
((whiskering_right C D E).obj F).map_iso α
def
category_theory.iso_whisker_right
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
If `α : G ≅ H` then `iso_whisker_right α F : (G ⋙ F) ≅ (H ⋙ F)` has components `F.map_iso (α.app X)`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iso_whisker_right_hom {G H : C ⥤ D} (α : G ≅ H) (F : D ⥤ E) : (iso_whisker_right α F).hom = whisker_right α.hom F
rfl
lemma
category_theory.iso_whisker_right_hom
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
iso_whisker_right_inv {G H : C ⥤ D} (α : G ≅ H) (F : D ⥤ E) : (iso_whisker_right α F).inv = whisker_right α.inv F
rfl
lemma
category_theory.iso_whisker_right_inv
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_iso_whisker_left (F : C ⥤ D) {G H : D ⥤ E} (α : G ⟶ H) [is_iso α] : is_iso (whisker_left F α)
is_iso.of_iso (iso_whisker_left F (as_iso α))
instance
category_theory.is_iso_whisker_left
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_iso_whisker_right {G H : C ⥤ D} (α : G ⟶ H) (F : D ⥤ E) [is_iso α] : is_iso (whisker_right α F)
is_iso.of_iso (iso_whisker_right (as_iso α) F)
instance
category_theory.is_iso_whisker_right
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
whisker_left_twice (F : B ⥤ C) (G : C ⥤ D) {H K : D ⥤ E} (α : H ⟶ K) : whisker_left F (whisker_left G α) = whisker_left (F ⋙ G) α
rfl
lemma
category_theory.whisker_left_twice
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
whisker_right_twice {H K : B ⥤ C} (F : C ⥤ D) (G : D ⥤ E) (α : H ⟶ K) : whisker_right (whisker_right α F) G = whisker_right α (F ⋙ G)
rfl
lemma
category_theory.whisker_right_twice
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
whisker_right_left (F : B ⥤ C) {G H : C ⥤ D} (α : G ⟶ H) (K : D ⥤ E) : whisker_right (whisker_left F α) K = whisker_left F (whisker_right α K)
rfl
lemma
category_theory.whisker_right_left
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
left_unitor (F : A ⥤ B) : ((𝟭 A) ⋙ F) ≅ F
{ hom := { app := λ X, 𝟙 (F.obj X) }, inv := { app := λ X, 𝟙 (F.obj X) } }
def
category_theory.functor.left_unitor
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
The left unitor, a natural isomorphism `((𝟭 _) ⋙ F) ≅ F`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
right_unitor (F : A ⥤ B) : (F ⋙ (𝟭 B)) ≅ F
{ hom := { app := λ X, 𝟙 (F.obj X) }, inv := { app := λ X, 𝟙 (F.obj X) } }
def
category_theory.functor.right_unitor
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
The right unitor, a natural isomorphism `(F ⋙ (𝟭 B)) ≅ F`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
associator (F : A ⥤ B) (G : B ⥤ C) (H : C ⥤ D) : ((F ⋙ G) ⋙ H) ≅ (F ⋙ (G ⋙ H))
{ hom := { app := λ _, 𝟙 _ }, inv := { app := λ _, 𝟙 _ } }
def
category_theory.functor.associator
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
The associator for functors, a natural isomorphism `((F ⋙ G) ⋙ H) ≅ (F ⋙ (G ⋙ H))`. (In fact, `iso.refl _` will work here, but it tends to make Lean slow later, and it's usually best to insert explicit associators.)
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
assoc (F : A ⥤ B) (G : B ⥤ C) (H : C ⥤ D) : ((F ⋙ G) ⋙ H) = (F ⋙ (G ⋙ H))
rfl
lemma
category_theory.functor.assoc
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
triangle (F : A ⥤ B) (G : B ⥤ C) : (associator F (𝟭 B) G).hom ≫ (whisker_left F (left_unitor G).hom) = (whisker_right (right_unitor F).hom G)
by { ext, dsimp, simp }
lemma
category_theory.functor.triangle
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
pentagon : (whisker_right (associator F G H).hom K) ≫ (associator F (G ⋙ H) K).hom ≫ (whisker_left F (associator G H K).hom) = ((associator (F ⋙ G) H K).hom ≫ (associator F G (H ⋙ K)).hom)
by { ext, dsimp, simp }
lemma
category_theory.functor.pentagon
category_theory
src/category_theory/whiskering.lean
[ "category_theory.isomorphism", "category_theory.functor.category", "category_theory.functor.fully_faithful" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
with_terminal : Type u | of : C → with_terminal | star : with_terminal
inductive
category_theory.with_terminal
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[]
Formally adjoin a terminal object to a category.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
with_initial : Type u | of : C → with_initial | star : with_initial
inductive
category_theory.with_initial
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[]
Formally adjoin an initial object to a category.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom : with_terminal C → with_terminal C → Type v
| (of X) (of Y) := X ⟶ Y | star (of X) := pempty | _ star := punit
def
category_theory.with_terminal.hom
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[ "pempty" ]
Morphisms for `with_terminal C`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
id : Π (X : with_terminal C), hom X X
| (of X) := 𝟙 _ | star := punit.star
def
category_theory.with_terminal.id
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[]
Identity morphisms for `with_terminal C`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp : Π {X Y Z : with_terminal C}, hom X Y → hom Y Z → hom X Z
| (of X) (of Y) (of Z) := λ f g, f ≫ g | (of X) _ star := λ f g, punit.star | star (of X) _ := λ f g, pempty.elim f | _ star (of Y) := λ f g, pempty.elim g | star star star := λ _ _, punit.star
def
category_theory.with_terminal.comp
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[ "pempty.elim" ]
Composition of morphisms for `with_terminal C`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
incl : C ⥤ (with_terminal C)
{ obj := of, map := λ X Y f, f }
def
category_theory.with_terminal.incl
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[]
The inclusion from `C` into `with_terminal C`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map {D : Type*} [category D] (F : C ⥤ D) : with_terminal C ⥤ with_terminal D
{ obj := λ X, match X with | of x := of $ F.obj x | star := star end, map := λ X Y f, match X, Y, f with | of x, of y, f := F.map f | of x, star, punit.star := punit.star | star, star, punit.star := punit.star end }
def
category_theory.with_terminal.map
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[]
Map `with_terminal` with respect to a functor `F : C ⥤ D`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
star_terminal : limits.is_terminal (star : with_terminal C)
limits.is_terminal.of_unique _
def
category_theory.with_terminal.star_terminal
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[]
`with_terminal.star` is terminal.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift {D : Type*} [category D] {Z : D} (F : C ⥤ D) (M : Π (x : C), F.obj x ⟶ Z) (hM : ∀ (x y : C) (f : x ⟶ y), F.map f ≫ M y = M x) : (with_terminal C) ⥤ D
{ obj := λ X, match X with | of x := F.obj x | star := Z end, map := λ X Y f, match X, Y, f with | of x, of y, f := F.map f | of x, star, punit.star := M x | star, star, punit.star := 𝟙 Z end }
def
category_theory.with_terminal.lift
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[ "lift" ]
Lift a functor `F : C ⥤ D` to `with_term C ⥤ D`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
incl_lift {D : Type*} [category D] {Z : D} (F : C ⥤ D) (M : Π (x : C), F.obj x ⟶ Z) (hM : ∀ (x y : C) (f : x ⟶ y), F.map f ≫ M y = M x) : incl ⋙ lift F M hM ≅ F
{ hom := { app := λ X, 𝟙 _ }, inv := { app := λ X, 𝟙 _ } }
def
category_theory.with_terminal.incl_lift
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[ "lift" ]
The isomorphism between `incl ⋙ lift F _ _` with `F`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_star {D : Type*} [category D] {Z : D} (F : C ⥤ D) (M : Π (x : C), F.obj x ⟶ Z) (hM : ∀ (x y : C) (f : x ⟶ y), F.map f ≫ M y = M x) : (lift F M hM).obj star ≅ Z
eq_to_iso rfl
def
category_theory.with_terminal.lift_star
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[ "lift" ]
The isomorphism between `(lift F _ _).obj with_terminal.star` with `Z`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_map_lift_star {D : Type*} [category D] {Z : D} (F : C ⥤ D) (M : Π (x : C), F.obj x ⟶ Z) (hM : ∀ (x y : C) (f : x ⟶ y), F.map f ≫ M y = M x) (x : C) : (lift F M hM).map (star_terminal.from (incl.obj x)) ≫ (lift_star F M hM).hom = (incl_lift F M hM).hom.app x ≫ M x
begin erw [category.id_comp, category.comp_id], refl, end
lemma
category_theory.with_terminal.lift_map_lift_star
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[ "lift" ]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_unique {D : Type*} [category D] {Z : D} (F : C ⥤ D) (M : Π (x : C), F.obj x ⟶ Z) (hM : ∀ (x y : C) (f : x ⟶ y), F.map f ≫ M y = M x) (G : with_terminal C ⥤ D) (h : incl ⋙ G ≅ F) (hG : G.obj star ≅ Z) (hh : ∀ x : C, G.map (star_terminal.from (incl.obj x)) ≫ hG.hom = h.hom.app x ≫ M x) : G ≅ lift F M hM
nat_iso.of_components (λ X, match X with | of x := h.app x | star := hG end) begin rintro (X|X) (Y|Y) f, { apply h.hom.naturality }, { cases f, exact hh _ }, { cases f, }, { cases f, change G.map (𝟙 _) ≫ hG.hom = hG.hom ≫ 𝟙 _, simp } end
def
category_theory.with_terminal.lift_unique
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[ "lift", "lift_unique" ]
The uniqueness of `lift`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_to_terminal {D : Type*} [category D] {Z : D} (F : C ⥤ D) (hZ : limits.is_terminal Z) : with_terminal C ⥤ D
lift F (λ x, hZ.from _) (λ x y f, hZ.hom_ext _ _)
def
category_theory.with_terminal.lift_to_terminal
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[ "lift" ]
A variant of `lift` with `Z` a terminal object.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
incl_lift_to_terminal {D : Type*} [category D] {Z : D} (F : C ⥤ D) (hZ : limits.is_terminal Z) : incl ⋙ lift_to_terminal F hZ ≅ F
incl_lift _ _ _
def
category_theory.with_terminal.incl_lift_to_terminal
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[]
A variant of `incl_lift` with `Z` a terminal object.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift_to_terminal_unique {D : Type*} [category D] {Z : D} (F : C ⥤ D) (hZ : limits.is_terminal Z) (G : with_terminal C ⥤ D) (h : incl ⋙ G ≅ F) (hG : G.obj star ≅ Z) : G ≅ lift_to_terminal F hZ
lift_unique F (λ z, hZ.from _) (λ x y f, hZ.hom_ext _ _) G h hG (λ x, hZ.hom_ext _ _)
def
category_theory.with_terminal.lift_to_terminal_unique
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[ "lift_unique" ]
A variant of `lift_unique` with `Z` a terminal object.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom_from (X : C) : incl.obj X ⟶ star
star_terminal.from _
def
category_theory.with_terminal.hom_from
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[]
Constructs a morphism to `star` from `of X`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
is_iso_of_from_star {X : with_terminal C} (f : star ⟶ X) : is_iso f
by tidy
instance
category_theory.with_terminal.is_iso_of_from_star
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[]
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
hom : with_initial C → with_initial C → Type v
| (of X) (of Y) := X ⟶ Y | (of X) _ := pempty | star _ := punit
def
category_theory.with_initial.hom
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[ "pempty" ]
Morphisms for `with_initial C`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
id : Π (X : with_initial C), hom X X
| (of X) := 𝟙 _ | star := punit.star
def
category_theory.with_initial.id
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[]
Identity morphisms for `with_initial C`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
comp : Π {X Y Z : with_initial C}, hom X Y → hom Y Z → hom X Z
| (of X) (of Y) (of Z) := λ f g, f ≫ g | star _ (of X) := λ f g, punit.star | _ (of X) star := λ f g, pempty.elim g | (of Y) star _ := λ f g, pempty.elim f | star star star := λ _ _, punit.star
def
category_theory.with_initial.comp
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[ "pempty.elim" ]
Composition of morphisms for `with_initial C`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
incl : C ⥤ (with_initial C)
{ obj := of, map := λ X Y f, f }
def
category_theory.with_initial.incl
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[]
The inclusion of `C` into `with_initial C`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
map {D : Type*} [category D] (F : C ⥤ D) : with_initial C ⥤ with_initial D
{ obj := λ X, match X with | of x := of $ F.obj x | star := star end, map := λ X Y f, match X, Y, f with | of x, of y, f := F.map f | star, of x, punit.star := punit.star | star, star, punit.star := punit.star end }
def
category_theory.with_initial.map
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[]
Map `with_initial` with respect to a functor `F : C ⥤ D`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
star_initial : limits.is_initial (star : with_initial C)
limits.is_initial.of_unique _
def
category_theory.with_initial.star_initial
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[]
`with_initial.star` is initial.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
lift {D : Type*} [category D] {Z : D} (F : C ⥤ D) (M : Π (x : C), Z ⟶ F.obj x) (hM : ∀ (x y : C) (f : x ⟶ y), M x ≫ F.map f = M y) : (with_initial C) ⥤ D
{ obj := λ X, match X with | of x := F.obj x | star := Z end, map := λ X Y f, match X, Y, f with | of x, of y, f := F.map f | star, of x, punit.star := M _ | star, star, punit.star := 𝟙 _ end }
def
category_theory.with_initial.lift
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[ "lift" ]
Lift a functor `F : C ⥤ D` to `with_initial C ⥤ D`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83
incl_lift {D : Type*} [category D] {Z : D} (F : C ⥤ D) (M : Π (x : C), Z ⟶ F.obj x) (hM : ∀ (x y : C) (f : x ⟶ y), M x ≫ F.map f = M y) : incl ⋙ lift F M hM ≅ F
{ hom := { app := λ X, 𝟙 _ }, inv := { app := λ X, 𝟙 _ } }
def
category_theory.with_initial.incl_lift
category_theory
src/category_theory/with_terminal.lean
[ "category_theory.limits.shapes.terminal" ]
[ "lift" ]
The isomorphism between `incl ⋙ lift F _ _` with `F`.
https://github.com/leanprover-community/mathlib
65a1391a0106c9204fe45bc73a039f056558cb83