Equivariant homomorphisms #
Main definitions #
MulActionHom φ X Y
, the type of equivariant functions fromX
toY
, whereφ : M → N
is a map,M
acting on the typeX
andN
acting on the type ofY
.AddActionHom φ X Y
is its additive version.DistribMulActionHom φ A B
, the type of equivariant additive monoid homomorphisms fromA
toB
, whereφ : M → N
is a morphism of monoids,M
acting on the additive monoidA
andN
acting on the additive monoid ofB
SMulSemiringHom φ R S
, the type of equivariant ring homomorphisms fromR
toS
, whereφ : M → N
is a morphism of monoids,M
acting on the ringR
andN
acting on the ringS
.
The above types have corresponding classes:
MulActionHomClass F φ X Y
states thatF
is a type of bundledX → Y
homs which areφ
-equivariant;AddActionHomClass F φ X Y
is its additive version.DistribMulActionHomClass F φ A B
states thatF
is a type of bundledA → B
homs preserving the additive monoid structure andφ
-equivariantSMulSemiringHomClass F φ R S
states thatF
is a type of bundledR → S
homs preserving the ring structure andφ
-equivariant
Notation #
We introduce the following notation to code equivariant maps
(the subscript index ₑ
is for equivariant) :
X →ₑ[φ] Y
isMulActionHom φ X Y
andAddActionHom φ X Y
A →ₑ+[φ] B
isDistribMulActionHom φ A B
.R →ₑ+*[φ] S
isMulSemiringActionHom φ R S
.
When M = N
and φ = MonoidHom.id M
, we provide the backward compatible notation :
X →[M] Y
isMulActionHom (@id M) X Y
andAddActionHom (@id M) X Y
A →+[M] B
isDistribMulActionHom (MonoidHom.id M) A B
R →+*[M] S
isMulSemiringActionHom (MonoidHom.id M) R S
The notation for MulActionHom
and AddActionHom
is the same, because it is unlikely
that it could lead to confusion — unless one needs types M
and X
with simultaneous
instances of Mul M
, Add M
, SMul M X
and VAdd M X
…
Equivariant functions :
When φ : M → N
is a function, and types X
and Y
are endowed with additive actions
of M
and N
, a function f : X → Y
is φ
-equivariant if f (m +ᵥ x) = (φ m) +ᵥ (f x)
.
- toFun : X → Y
The underlying function.
The proposition that the function commutes with the additive actions.
Instances For
Equivariant functions :
When φ : M → N
is a function, and types X
and Y
are endowed with actions of M
and N
,
a function f : X → Y
is φ
-equivariant if f (m • x) = (φ m) • (f x)
.
- toFun : X → Y
The underlying function.
The proposition that the function commutes with the actions.
Instances For
φ
-equivariant functions X → Y
,
where φ : M → N
, where M
and N
act on X
and Y
respectively.
Equations
Instances For
M
-equivariant functions X → Y
with respect to the action of M
.
This is the same as X →ₑ[@id M] Y
.
Equations
Instances For
φ
-equivariant functions X → Y
,
where φ : M → N
, where M
and N
act additively on X
and Y
respectively
We use the same notation as for multiplicative actions, as conflicts are unlikely.
Equations
Instances For
M
-equivariant functions X → Y
with respect to the additive action of M
.
This is the same as X →ₑ[@id M] Y
.
We use the same notation as for multiplicative actions, as conflicts are unlikely.
Equations
Instances For
AddActionSemiHomClass F φ X Y
states that
F
is a type of morphisms which are φ
-equivariant.
You should extend this class when you extend AddActionHom
.
The proposition that the function preserves the action.
Instances
MulActionSemiHomClass F φ X Y
states that
F
is a type of morphisms which are φ
-equivariant.
You should extend this class when you extend MulActionHom
.
The proposition that the function preserves the action.
Instances
MulActionHomClass F M X Y
states that F
is a type of
morphisms which are equivariant with respect to actions of M
This is an abbreviation of MulActionSemiHomClass
.
Equations
Instances For
MulActionHomClass F M X Y
states that F
is a type of
morphisms which are equivariant with respect to actions of M
This is an abbreviation of MulActionSemiHomClass
.
Equations
Instances For
Turn an element of a type F
satisfying MulActionSemiHomClass F φ X Y
into an actual MulActionHom
.
This is declared as the default coercion from F
to MulActionSemiHom φ X Y
.
Equations
Instances For
Turn an element of a type F
satisfying AddActionSemiHomClass F φ X Y
into an actual AddActionHom
.
This is declared as the default coercion from F
to AddActionSemiHom φ X Y
.
Equations
Instances For
Any type satisfying MulActionSemiHomClass
can be cast into MulActionHom
via
MulActionHomSemiClass.toMulActionHom
.
Equations
If Y/X/M forms a scalar tower, any map X → Y preserving X-action also preserves M-action.
The inverse of a bijective equivariant map is equivariant.
Equations
Instances For
The inverse of a bijective equivariant map is equivariant.
Equations
Instances For
The inverse of a bijective equivariant map is equivariant.
Equations
Instances For
The inverse of a bijective equivariant map is equivariant.
Equations
Instances For
Evaluation at a point as a MulActionHom
.
Equations
Instances For
Evaluation at a point as an AddActionHom
.
Equations
Instances For
Equations
Equations
Equations
Equations
Equations
Equations
Equations
Equations
Equivariant additive monoid homomorphisms.
- toFun : A → B
Instances For
Equivariant additive monoid homomorphisms.
Equations
Instances For
Equivariant additive monoid homomorphisms.
Equations
Instances For
DistribMulActionSemiHomClass F φ A B
states that F
is a type of morphisms
preserving the additive monoid structure and equivariant with respect to φ
.
You should extend this class when you extend DistribMulActionSemiHom
.
Instances
DistribMulActionHomClass F M A B
states that F
is a type of morphisms preserving
the additive monoid structure and equivariant with respect to the action of M
.
It is an abbreviation to DistribMulActionHomClass F (MonoidHom.id M) A B
You should extend this class when you extend DistribMulActionHom
.
Equations
Instances For
Turn an element of a type F
satisfying MulActionHomClass F M X Y
into an actual
MulActionHom
. This is declared as the default coercion from F
to MulActionHom M X Y
.
Equations
Instances For
Any type satisfying MulActionHomClass
can be cast into MulActionHom
via MulActionHomClass.toMulActionHom
.
Equations
If DistribMulAction
of M
and N
on A
commute,
then for each c : M
, (c • ·)
is an N
-action additive homomorphism.
Equations
Instances For
The identity map as an equivariant additive monoid homomorphism.
Equations
Instances For
Equations
Composition of two equivariant additive monoid homomorphisms.
Equations
Instances For
The inverse of a bijective DistribMulActionHom
is a DistribMulActionHom
.
Equations
Instances For
Equivariant ring homomorphisms.
- toFun : R → S
Instances For
Equivariant ring homomorphisms.
Equations
Instances For
Equivariant ring homomorphisms.
Equations
Instances For
MulSemiringActionHomClass F φ R S
states that F
is a type of morphisms preserving
the ring structure and equivariant with respect to φ
.
You should extend this class when you extend MulSemiringActionHom
.
Instances
MulSemiringActionHomClass F M R S
states that F
is a type of morphisms preserving
the ring structure and equivariant with respect to a DistribMulAction
of M
on R
and S
.
Equations
Instances For
Turn an element of a type F
satisfying MulSemiringActionHomClass F M R S
into an actual
MulSemiringActionHom
. This is declared as the default coercion from F
to
MulSemiringActionHom M X Y
.
Equations
Instances For
Any type satisfying MulSemiringActionHomClass
can be cast into MulSemiringActionHom
via
MulSemiringActionHomClass.toMulSemiringActionHom
.
Equations
The identity map as an equivariant ring homomorphism.
Equations
Instances For
Composition of two equivariant additive ring homomorphisms.
Equations
Instances For
The inverse of a bijective MulSemiringActionHom
is a MulSemiringActionHom
.
Equations
Instances For
The inverse of a bijective MulSemiringActionHom
is a MulSemiringActionHom
.