Equivariant homomorphisms #
Main definitions #
MulActionHom M X Y, the type of equivariant functions fromXtoY, whereMis a monoid that acts on the typesXandY.DistribMulActionHom M A B, the type of equivariant additive monoid homomorphisms fromAtoB, whereMis a monoid that acts on the additive monoidsAandB.MulSemiringActionHom M R S, the type of equivariant ring homomorphisms fromRtoS, whereMis a monoid that acts on the ringsRandS.
The above types have corresponding classes:
SMulHomClass F M X Ystates thatFis a type of bundledX → Yhoms preserving scalar multiplication byMDistribMulActionHomClass F M A Bstates thatFis a type of bundledA → Bhoms preserving the additive monoid structure and scalar multiplication byMMulSemiringActionHomClass F M R Sstates thatFis a type of bundledR → Shoms preserving the ring structure and scalar multiplication byM
Notations #
X →[M] YisMulActionHom M X Y.A →+[M] BisDistribMulActionHom M A B.R →+*[M] SisMulSemiringActionHom M R S.
Equivariant functions.
- toFun : X → Y
The underlying function.
- map_smul' : ∀ (m : M') (x : X), MulActionHom.toFun s (m • x) = m • MulActionHom.toFun s x
The proposition that the function preserves the action.
Instances For
Equivariant functions.
Equations
- One or more equations did not get rendered due to their size.
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SMulHomClass F M X Y states that F is a type of morphisms preserving
scalar multiplication by M.
You should extend this class when you extend MulActionHom.
- coe : F → X → Y
- coe_injective' : Function.Injective FunLike.coe
The proposition that the function preserves the action.
Instances
Equations
- instSMulHomClassMulActionHom M' X Y = SMulHomClass.mk (_ : ∀ (self : X →[M'] Y) (m : M') (x : X), MulActionHom.toFun self (m • x) = m • MulActionHom.toFun self x)
Turn an element of a type F satisfying SMulHomClass F M X Y into an actual
MulActionHom. This is declared as the default coercion from F to MulActionHom M X Y.
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Any type satisfying SMulHomClass can be cast into MulActionHom via
SMulHomClass.toMulActionHom.
Equations
- MulActionHom.instCoeTCMulActionHom = { coe := SMulHomClass.toMulActionHom }
If Y/X/M forms a scalar tower, any map X → Y preserving X-action also preserves M-action.
Equations
- IsScalarTower.smulHomClass M' X Y F = SMulHomClass.mk (_ : ∀ (f : F) (m : M') (x : X), f (m • x) = m • f x)
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The inverse of a bijective equivariant map is equivariant.
Equations
- MulActionHom.inverse f g h₁ h₂ = { toFun := g, map_smul' := (_ : ∀ (m : M) (x : B), g (m • x) = m • g x) }
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If actions of M and N on α commute, then for c : M, (c • · : α → α) is an N-action
homomorphism.
Equations
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Equivariant additive monoid homomorphisms.
- toFun : A → B
- map_smul' : ∀ (m : M) (x : A), MulActionHom.toFun s.toMulActionHom (m • x) = m • MulActionHom.toFun s.toMulActionHom x
- map_zero' : MulActionHom.toFun s.toMulActionHom 0 = 0
The proposition that the function preserves 0
- map_add' : ∀ (x y : A), MulActionHom.toFun s.toMulActionHom (x + y) = MulActionHom.toFun s.toMulActionHom x + MulActionHom.toFun s.toMulActionHom y
The proposition that the function preserves addition
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Reinterpret an equivariant additive monoid homomorphism as an additive monoid homomorphism.
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Equivariant additive monoid homomorphisms.
Equations
- One or more equations did not get rendered due to their size.
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DistribMulActionHomClass F M A B states that F is a type of morphisms preserving
the additive monoid structure and scalar multiplication by M.
You should extend this class when you extend DistribMulActionHom.
- coe : F → A → B
- coe_injective' : Function.Injective FunLike.coe
The proposition that the function preserves addition
- map_zero : ∀ (f : F), f 0 = 0
The proposition that the function preserves 0
Instances
Equations
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Turn an element of a type F satisfying SMulHomClass F M X Y into an actual
MulActionHom. This is declared as the default coercion from F to MulActionHom M X Y.
Equations
- One or more equations did not get rendered due to their size.
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Any type satisfying SMulHomClass can be cast into MulActionHom via
SMulHomClass.toMulActionHom.
Equations
- DistribMulActionHom.instCoeTCDistribMulActionHom = { coe := DistribMulActionHomClass.toDistribMulActionHom }
The identity map as an equivariant additive monoid homomorphism.
Equations
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Instances For
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Equations
- DistribMulActionHom.instOneDistribMulActionHom = { one := DistribMulActionHom.id M }
Equations
- DistribMulActionHom.instInhabitedDistribMulActionHom = { default := 0 }
Composition of two equivariant additive monoid homomorphisms.
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The inverse of a bijective DistribMulActionHom is a DistribMulActionHom.
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If DistribMulAction of M and N on A commute, then for each c : M, (c • ·) is an
N-action additive homomorphism.
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- One or more equations did not get rendered due to their size.
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Equivariant ring homomorphisms.
- toFun : R → S
- map_smul' : ∀ (m : M) (x : R), MulActionHom.toFun s.toMulActionHom (m • x) = m • MulActionHom.toFun s.toMulActionHom x
- map_zero' : MulActionHom.toFun s.toMulActionHom 0 = 0
- map_add' : ∀ (x y : R), MulActionHom.toFun s.toMulActionHom (x + y) = MulActionHom.toFun s.toMulActionHom x + MulActionHom.toFun s.toMulActionHom y
- map_one' : MulActionHom.toFun s.toMulActionHom 1 = 1
The proposition that the function preserves 1
- map_mul' : ∀ (x y : R), MulActionHom.toFun s.toMulActionHom (x * y) = MulActionHom.toFun s.toMulActionHom x * MulActionHom.toFun s.toMulActionHom y
The proposition that the function preserves multiplication
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Reinterpret an equivariant ring homomorphism as a ring homomorphism.
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- One or more equations did not get rendered due to their size.
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Equivariant ring homomorphisms.
Equations
- One or more equations did not get rendered due to their size.
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MulSemiringActionHomClass F M R S states that F is a type of morphisms preserving
the ring structure and scalar multiplication by M.
You should extend this class when you extend MulSemiringActionHom.
- coe : F → R → S
- coe_injective' : Function.Injective FunLike.coe
- map_zero : ∀ (f : F), f 0 = 0
The proposition that the function preserves multiplication
- map_one : ∀ (f : F), f 1 = 1
The proposition that the function preserves 1
Instances
Equations
- One or more equations did not get rendered due to their size.
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
- One or more equations did not get rendered due to their size.
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Any type satisfying MulSemiringActionHomClass can be cast into MulSemiringActionHom via
MulSemiringActionHomClass.toMulSemiringActionHom.
Equations
- MulSemiringActionHom.instCoeTCMulSemiringActionHom = { coe := MulSemiringActionHomClass.toMulSemiringActionHom }
The identity map as an equivariant ring homomorphism.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Composition of two equivariant additive monoid homomorphisms.
Equations
- One or more equations did not get rendered due to their size.