Properties of morphisms #
We provide the basic framework for talking about properties of morphisms. The following meta-properties are defined
RespectsIso
:P
respects isomorphisms ifP f → P (e ≫ f)
andP f → P (f ≫ e)
, wheree
is an isomorphism.StableUnderComposition
:P
is stable under composition ifP f → P g → P (f ≫ g)
.StableUnderBaseChange
:P
is stable under base change if in all pullback squares, the left map satisfiesP
if the right map satisfies it.StableUnderCobaseChange
:P
is stable under cobase change if in all pushout squares, the right map satisfiesP
if the left map satisfies it.
A MorphismProperty C
is a class of morphisms between objects in C
.
Instances For
The morphism property in Cᵒᵖ
associated to a morphism property in C
Instances For
The morphism property in C
associated to a morphism property in Cᵒᵖ
Instances For
The inverse image of a MorphismProperty D
by a functor C ⥤ D
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The image (up to isomorphisms) of a MorphismProperty C
by a functor C ⥤ D
Instances For
A morphism property RespectsIso
if it still holds when composed with an isomorphism
Instances For
The closure by isomorphisms of a MorphismProperty
Instances For
A morphism property is StableUnderComposition
if the composition of two such morphisms
still falls in the class.
Instances For
A morphism property is StableUnderInverse
if the inverse of a morphism satisfying
the property still falls in the class.
Instances For
A morphism property is StableUnderBaseChange
if the base change of such a morphism
still falls in the class.
Instances For
A morphism property is StableUnderCobaseChange
if the cobase change of such a morphism
still falls in the class.
Instances For
If P : MorphismProperty C
and F : C ⥤ D
, then
P.IsInvertedBy F
means that all morphisms in P
are mapped by F
to isomorphisms in D
.
Instances For
Given app : Π X, F₁.obj X ⟶ F₂.obj X
where F₁
and F₂
are two functors,
this is the morphism_property C
satisfied by the morphisms in C
with respect
to whom app
is natural.
Instances For
The MorphismProperty C
satisfied by isomorphisms in C
.
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The MorphismProperty C
satisfied by monomorphisms in C
.
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The MorphismProperty C
satisfied by epimorphisms in C
.
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The full subcategory of C ⥤ D
consisting of functors inverting morphisms in W
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A constructor for W.FunctorsInverting D
Instances For
For P : MorphismProperty C
, P.diagonal
is a morphism property that holds for f : X ⟶ Y
whenever P
holds for X ⟶ Y xₓ Y
.
Instances For
P.universally
holds for a morphism f : X ⟶ Y
iff P
holds for all X ×[Y] Y' ⟶ Y'
.
Instances For
Injectiveness (in a concrete category) as a MorphismProperty
Instances For
Surjectiveness (in a concrete category) as a MorphismProperty
Instances For
Bijectiveness (in a concrete category) as a MorphismProperty
Instances For
- id_mem' : ∀ (X : C), W (CategoryTheory.CategoryStruct.id X)
for all
X : C
, the identity ofX
satisfies the morphism property
Typeclass expressing that a morphism property contain identities.
Instances
- id_mem' : ∀ (X : C), W (CategoryTheory.CategoryStruct.id X)
- stableUnderComposition : CategoryTheory.MorphismProperty.StableUnderComposition W
compatibility of
A morphism property is multiplicative if it contains identities and is stable by composition.