Maps of monoid algebras #
This file defines maps of monoid algebras along both the ring and monoid arguments.
Multiplicative monoids #
Given a function f : M → N between magmas, return the corresponding map R[M] → R[N] obtained
by summing the coefficients along each fiber of f.
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Given a function f : M → N between magmas, return the corresponding map R[M] → R[N] obtained
by summing the coefficients along each fiber of f.
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If f : G → H is a multiplicative homomorphism between two monoids, then
MonoidAlgebra.mapDomain f is a ring homomorphism between their monoid algebras.
See also MulEquiv.monoidAlgebraCongrRight.
Equations
- MonoidAlgebra.mapDomainNonUnitalRingHom R f = { toFun := MonoidAlgebra.mapDomain ⇑f, map_mul' := ⋯, map_zero' := ⋯, map_add' := ⋯ }
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If f : G → H is a multiplicative homomorphism between two additive monoids, then
AddMonoidAlgebra.mapDomain f is a ring homomorphism between their additive monoid algebras.
Equations
- AddMonoidAlgebra.mapDomainNonUnitalRingHom R f = { toFun := AddMonoidAlgebra.mapDomain ⇑f, map_mul' := ⋯, map_zero' := ⋯, map_add' := ⋯ }
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Equivalent monoids have additively isomorphic monoid algebras.
MonoidAlgebra.mapDomain as an AddEquiv.
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- One or more equations did not get rendered due to their size.
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Equivalent additive monoids have additively isomorphic additive monoid algebras.
AddMonoidAlgebra.mapDomain as an AddEquiv.
Equations
- One or more equations did not get rendered due to their size.
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Additively isomorphic rings have additively isomorphic monoid algebras.
Finsupp.mapRange as an AddEquiv.
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- One or more equations did not get rendered due to their size.
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Additively isomorphic rings have additively isomorphic additive monoid algebras.
Finsupp.mapRange as an AddEquiv.
Equations
- One or more equations did not get rendered due to their size.
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If f : G → H is a multiplicative homomorphism between two monoids, then
MonoidAlgebra.mapDomain f is a ring homomorphism between their monoid algebras.
Equations
- MonoidAlgebra.mapDomainRingHom R f = { toFun := MonoidAlgebra.mapDomain ⇑f, map_one' := ⋯, map_mul' := ⋯, map_zero' := ⋯, map_add' := ⋯ }
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If f : G → H is a multiplicative homomorphism between two additive monoids, then
AddMonoidAlgebra.mapDomain f is a ring homomorphism between their additive monoid algebras.
Equations
- AddMonoidAlgebra.mapDomainRingHom R f = { toFun := AddMonoidAlgebra.mapDomain ⇑f, map_one' := ⋯, map_mul' := ⋯, map_zero' := ⋯, map_add' := ⋯ }
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The ring homomorphism of monoid algebras induced by a homomorphism of the base rings.
Equations
- MonoidAlgebra.mapRangeRingHom M f = { toFun := Finsupp.mapRange ⇑f ⋯, map_one' := ⋯, map_mul' := ⋯, map_zero' := ⋯, map_add' := ⋯ }
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The ring homomorphism of additive monoid algebras induced by a homomorphism of the base rings.
Equations
- AddMonoidAlgebra.mapRangeRingHom M f = { toFun := Finsupp.mapRange ⇑f ⋯, map_one' := ⋯, map_mul' := ⋯, map_zero' := ⋯, map_add' := ⋯ }
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Conversions between AddMonoidAlgebra and MonoidAlgebra #
We have not defined AddMonoidAlgebra k G = MonoidAlgebra k (Multiplicative G)
because historically this caused problems;
since the changes that have made nsmul definitional, this would be possible,
but for now we just construct the ring isomorphisms using RingEquiv.refl _.
The equivalence between AddMonoidAlgebra and MonoidAlgebra in terms of
Multiplicative
Equations
- One or more equations did not get rendered due to their size.
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The equivalence between MonoidAlgebra and AddMonoidAlgebra in terms of Additive
Equations
- One or more equations did not get rendered due to their size.