Monoid, group etc structures on M × N #
In this file we define one-binop (Monoid, Group etc) structures on M × N.
We also prove trivial simp lemmas, and define the following operations on MonoidHoms:
fst M N : M × N →* M,snd M N : M × N →* N: projectionsProd.fstandProd.sndasMonoidHoms;inl M N : M →* M × N,inr M N : N →* M × N: inclusions of first/second monoid into the product;f.prod g:M →* N × P: sendsxto(f x, g x);- When
Pis commutative,f.coprod g : M × N →* Psends(x, y)tof x * g y(without the commutativity assumption onP, seeMonoidHom.noncommPiCoprod); f.prodMap g : M × N → M' × N':prod.map f gas aMonoidHom, sends(x, y)to(f x, g y).
Main declarations #
mulMulHom/mulMonoidHom: Multiplication bundled as a multiplicative/monoid homomorphism.divMonoidHom: Division bundled as a monoid homomorphism.
Equations
- Prod.instOne = { one := (1, 1) }
Equations
- Prod.instZero = { zero := (0, 0) }
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- Prod.instMonoid = Monoid.mk ⋯ ⋯ (fun (z : ℕ) (a : M × N) => (Monoid.npow z a.1, Monoid.npow z a.2)) ⋯ ⋯
Equations
- Prod.instAddMonoid = AddMonoid.mk ⋯ ⋯ (fun (z : ℕ) (a : M × N) => (AddMonoid.nsmul z a.1, AddMonoid.nsmul z a.2)) ⋯ ⋯
Equations
- Prod.instDivInvMonoid = DivInvMonoid.mk ⋯ (fun (z : ℤ) (a : G × H) => (DivInvMonoid.zpow z a.1, DivInvMonoid.zpow z a.2)) ⋯ ⋯ ⋯
Equations
- Prod.subNegMonoid = SubNegMonoid.mk ⋯ (fun (z : ℤ) (a : G × H) => (SubNegMonoid.zsmul z a.1, SubNegMonoid.zsmul z a.2)) ⋯ ⋯ ⋯
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Prod.map as an AddMonoidHom
Equations
- f.prodMap g = (f.comp (AddHom.fst M N)).prod (g.comp (AddHom.snd M N))
Instances For
Coproduct of two MulHoms with the same codomain:
f.coprod g (p : M × N) = f p.1 * g p.2.
(Commutative codomain; for the general case, see MulHom.noncommCoprod)
Equations
- f.coprod g = f.comp (MulHom.fst M N) * g.comp (MulHom.snd M N)
Instances For
Coproduct of two AddHoms with the same codomain:
f.coprod g (p : M × N) = f p.1 + g p.2.
(Commutative codomain; for the general case, see AddHom.noncommCoprod)
Equations
- f.coprod g = f.comp (AddHom.fst M N) + g.comp (AddHom.snd M N)
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Given monoids M, N, the natural projection homomorphism from M × N to M.
Equations
- MonoidHom.fst M N = { toFun := Prod.fst, map_one' := ⋯, map_mul' := ⋯ }
Instances For
Given additive monoids A, B, the natural projection homomorphism
from A × B to A
Equations
- AddMonoidHom.fst M N = { toFun := Prod.fst, map_zero' := ⋯, map_add' := ⋯ }
Instances For
Given monoids M, N, the natural projection homomorphism from M × N to N.
Equations
- MonoidHom.snd M N = { toFun := Prod.snd, map_one' := ⋯, map_mul' := ⋯ }
Instances For
Given additive monoids A, B, the natural projection homomorphism
from A × B to B
Equations
- AddMonoidHom.snd M N = { toFun := Prod.snd, map_zero' := ⋯, map_add' := ⋯ }
Instances For
Given monoids M, N, the natural inclusion homomorphism from M to M × N.
Equations
- MonoidHom.inl M N = { toFun := fun (x : M) => (x, 1), map_one' := ⋯, map_mul' := ⋯ }
Instances For
Given additive monoids A, B, the natural inclusion homomorphism
from A to A × B.
Equations
- AddMonoidHom.inl M N = { toFun := fun (x : M) => (x, 0), map_zero' := ⋯, map_add' := ⋯ }
Instances For
Given monoids M, N, the natural inclusion homomorphism from N to M × N.
Equations
- MonoidHom.inr M N = { toFun := fun (y : N) => (1, y), map_one' := ⋯, map_mul' := ⋯ }
Instances For
Given additive monoids A, B, the natural inclusion homomorphism
from B to A × B.
Equations
- AddMonoidHom.inr M N = { toFun := fun (y : N) => (0, y), map_zero' := ⋯, map_add' := ⋯ }
Instances For
Combine two MonoidHoms f : M →* N, g : M →* P into f.prod g : M →* N × P
given by (f.prod g) x = (f x, g x).
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Combine two AddMonoidHoms f : M →+ N, g : M →+ P into
f.prod g : M →+ N × P given by (f.prod g) x = (f x, g x)
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prod.map as a MonoidHom.
Equations
- f.prodMap g = (f.comp (MonoidHom.fst M N)).prod (g.comp (MonoidHom.snd M N))
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prod.map as an AddMonoidHom.
Equations
- f.prodMap g = (f.comp (AddMonoidHom.fst M N)).prod (g.comp (AddMonoidHom.snd M N))
Instances For
Coproduct of two MonoidHoms with the same codomain:
f.coprod g (p : M × N) = f p.1 * g p.2.
(Commutative case; for the general case, see MonoidHom.noncommCoprod.)
Equations
- f.coprod g = f.comp (MonoidHom.fst M N) * g.comp (MonoidHom.snd M N)
Instances For
Coproduct of two AddMonoidHoms with the same codomain:
f.coprod g (p : M × N) = f p.1 + g p.2.
(Commutative case; for the general case, see AddHom.noncommCoprod.)
Equations
- f.coprod g = f.comp (AddMonoidHom.fst M N) + g.comp (AddMonoidHom.snd M N)
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The equivalence between M × N and N × M given by swapping the components
is multiplicative.
Equations
- MulEquiv.prodComm = { toEquiv := Equiv.prodComm M N, map_mul' := ⋯ }
Instances For
The equivalence between M × N and N × M given by swapping the
components is additive.
Equations
- AddEquiv.prodComm = { toEquiv := Equiv.prodComm M N, map_add' := ⋯ }
Instances For
The equivalence between (M × N) × P and M × (N × P) is multiplicative.
Equations
- MulEquiv.prodAssoc = { toEquiv := Equiv.prodAssoc M N P, map_mul' := ⋯ }
Instances For
The equivalence between (M × N) × P and M × (N × P) is additive.
Equations
- AddEquiv.prodAssoc = { toEquiv := Equiv.prodAssoc M N P, map_add' := ⋯ }
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Four-way commutativity of Prod. The name matches mul_mul_mul_comm.
Equations
- One or more equations did not get rendered due to their size.
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Four-way commutativity of Prod.
The name matches mul_mul_mul_comm
Equations
- One or more equations did not get rendered due to their size.
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Product of multiplicative isomorphisms; the maps come from Equiv.prodCongr.
Equations
- f.prodCongr g = { toEquiv := f.prodCongr g.toEquiv, map_mul' := ⋯ }
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Product of additive isomorphisms; the maps come from Equiv.prodCongr.
Equations
- f.prodCongr g = { toEquiv := f.prodCongr g.toEquiv, map_add' := ⋯ }
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Multiplying by the trivial monoid doesn't change the structure.
Equations
- MulEquiv.uniqueProd = { toEquiv := Equiv.uniqueProd M N, map_mul' := ⋯ }
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Multiplying by the trivial monoid doesn't change the structure.
Equations
- AddEquiv.uniqueProd = { toEquiv := Equiv.uniqueProd M N, map_add' := ⋯ }
Instances For
Multiplying by the trivial monoid doesn't change the structure.
Equations
- MulEquiv.prodUnique = { toEquiv := Equiv.prodUnique M N, map_mul' := ⋯ }
Instances For
Multiplying by the trivial monoid doesn't change the structure.
Equations
- AddEquiv.prodUnique = { toEquiv := Equiv.prodUnique M N, map_add' := ⋯ }
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The additive monoid equivalence between additive units of a product of two additive monoids, and the product of the additive units of each additive monoid.
Equations
- One or more equations did not get rendered due to their size.
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Canonical homomorphism of monoids from αˣ into α × αᵐᵒᵖ.
Used mainly to define the natural topology of αˣ.
Equations
- Units.embedProduct α = { toFun := fun (x : αˣ) => (↑x, MulOpposite.op ↑x⁻¹), map_one' := ⋯, map_mul' := ⋯ }
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Canonical homomorphism of additive monoids from AddUnits α into α × αᵃᵒᵖ.
Used mainly to define the natural topology of AddUnits α.
Equations
- AddUnits.embedProduct α = { toFun := fun (x : AddUnits α) => (↑x, AddOpposite.op ↑(-x)), map_zero' := ⋯, map_add' := ⋯ }
Instances For
Multiplication and division as homomorphisms #
Multiplication as a monoid homomorphism.
Equations
- mulMonoidHom = { toFun := mulMulHom.toFun, map_one' := ⋯, map_mul' := ⋯ }
Instances For
Addition as an additive monoid homomorphism.
Equations
- addAddMonoidHom = { toFun := addAddHom.toFun, map_zero' := ⋯, map_add' := ⋯ }
Instances For
Division as a monoid homomorphism.
Equations
- divMonoidHom = { toFun := fun (a : α × α) => a.1 / a.2, map_one' := ⋯, map_mul' := ⋯ }
Instances For
Subtraction as an additive monoid homomorphism.
Equations
- subAddMonoidHom = { toFun := fun (a : α × α) => a.1 - a.2, map_zero' := ⋯, map_add' := ⋯ }