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chore(Algebra/Group/Submonoid/Operations): move instances to new file (#21067)
Move declarations such as `Submonoid.smul` and `Submonoid.mulAction` into a new file, and shake some imports.
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‎Mathlib.lean

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@@ -355,6 +355,7 @@ import Mathlib.Algebra.Group.Submonoid.Defs
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import Mathlib.Algebra.Group.Submonoid.DistribMulAction
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import Mathlib.Algebra.Group.Submonoid.Finsupp
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import Mathlib.Algebra.Group.Submonoid.Membership
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import Mathlib.Algebra.Group.Submonoid.MulAction
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import Mathlib.Algebra.Group.Submonoid.MulOpposite
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import Mathlib.Algebra.Group.Submonoid.Operations
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import Mathlib.Algebra.Group.Submonoid.Pointwise

‎Mathlib/Algebra/Group/Submonoid/MulAction.lean

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/-
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Copyright (c) 2021 Eric Wieser. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Authors: Eric Wieser
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-/
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import Mathlib.Algebra.Group.Submonoid.Defs
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import Mathlib.Algebra.Group.Action.Defs
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/-!
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# Actions by `Submonoid`s
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These instances transfer the action by an element `m : M` of a monoid `M` written as `m • a` onto
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the action by an element `s : S` of a submonoid `S : Submonoid M` such that `s • a = (s : M) • a`.
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These instances work particularly well in conjunction with `Monoid.toMulAction`, enabling
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`s • m` as an alias for `↑s * m`.
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-/
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namespace Submonoid
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variable {M' : Type*} {α β : Type*}
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section MulOneClass
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variable [MulOneClass M']
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@[to_additive]
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instance smul [SMul M' α] (S : Submonoid M') : SMul S α :=
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SMul.comp _ S.subtype
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@[to_additive]
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instance smulCommClass_left [SMul M' β] [SMul α β] [SMulCommClass M' α β]
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(S : Submonoid M') : SMulCommClass S α β :=
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⟨fun a _ _ => smul_comm (a : M') _ _⟩
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@[to_additive]
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instance smulCommClass_right [SMul α β] [SMul M' β] [SMulCommClass α M' β]
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(S : Submonoid M') : SMulCommClass α S β :=
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⟨fun a s => smul_comm a (s : M')⟩
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/-- Note that this provides `IsScalarTower S M' M'` which is needed by `SMulMulAssoc`. -/
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instance isScalarTower [SMul α β] [SMul M' α] [SMul M' β] [IsScalarTower M' α β]
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(S : Submonoid M') :
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IsScalarTower S α β :=
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⟨fun a => smul_assoc (a : M')⟩
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section SMul
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variable [SMul M' α] {S : Submonoid M'}
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@[to_additive] lemma smul_def (g : S) (a : α) : g • a = (g : M') • a := rfl
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@[to_additive (attr := simp)]
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lemma mk_smul (g : M') (hg : g ∈ S) (a : α) : (⟨g, hg⟩ : S) • a = g • a := rfl
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end SMul
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end MulOneClass
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variable [Monoid M']
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/-- The action by a submonoid is the action by the underlying monoid. -/
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@[to_additive
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"The additive action by an `AddSubmonoid` is the action by the underlying `AddMonoid`. "]
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instance mulAction [MulAction M' α] (S : Submonoid M') : MulAction S α where
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one_smul := one_smul M'
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mul_smul m₁ m₂ := mul_smul (m₁ : M') m₂
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example {S : Submonoid M'} : IsScalarTower S M' M' := by infer_instance
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end Submonoid

‎Mathlib/Algebra/Group/Submonoid/Operations.lean

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@@ -8,6 +8,7 @@ import Mathlib.Algebra.Group.Action.Faithful
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import Mathlib.Algebra.Group.Nat.Defs
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import Mathlib.Algebra.Group.Prod
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import Mathlib.Algebra.Group.Submonoid.Basic
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import Mathlib.Algebra.Group.Submonoid.MulAction
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import Mathlib.Algebra.Group.TypeTags.Basic
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/-!
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ext
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rfl
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section Actions
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/-! ### Actions by `Submonoid`s
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These instances transfer the action by an element `m : M` of a monoid `M` written as `m • a` onto
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the action by an element `s : S` of a submonoid `S : Submonoid M` such that `s • a = (s : M) • a`.
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These instances work particularly well in conjunction with `Monoid.toMulAction`, enabling
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`s • m` as an alias for `↑s * m`.
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-/
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namespace Submonoid
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variable {M' : Type*} {α β : Type*}
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section MulOneClass
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variable [MulOneClass M']
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@[to_additive]
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instance smul [SMul M' α] (S : Submonoid M') : SMul S α :=
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SMul.comp _ S.subtype
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@[to_additive]
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instance smulCommClass_left [SMul M' β] [SMul α β] [SMulCommClass M' α β]
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(S : Submonoid M') : SMulCommClass S α β :=
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⟨fun a _ _ => smul_comm (a : M') _ _⟩
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@[to_additive]
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instance smulCommClass_right [SMul α β] [SMul M' β] [SMulCommClass α M' β]
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(S : Submonoid M') : SMulCommClass α S β :=
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⟨fun a s => smul_comm a (s : M')⟩
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/-- Note that this provides `IsScalarTower S M' M'` which is needed by `SMulMulAssoc`. -/
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instance isScalarTower [SMul α β] [SMul M' α] [SMul M' β] [IsScalarTower M' α β]
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(S : Submonoid M') :
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IsScalarTower S α β :=
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⟨fun a => smul_assoc (a : M')⟩
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section SMul
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variable [SMul M' α] {S : Submonoid M'}
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@[to_additive] lemma smul_def (g : S) (a : α) : g • a = (g : M') • a := rfl
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@[to_additive (attr := simp)]
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lemma mk_smul (g : M') (hg : g ∈ S) (a : α) : (⟨g, hg⟩ : S) • a = g • a := rfl
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instance faithfulSMul [FaithfulSMul M' α] : FaithfulSMul S α :=
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instance Submonoid.faithfulSMul {M' α : Type*} [MulOneClass M'] [SMul M' α] {S : Submonoid M'}
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[FaithfulSMul M' α] : FaithfulSMul S α :=
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⟨fun h => Subtype.ext <| eq_of_smul_eq_smul h⟩
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end SMul
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end MulOneClass
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variable [Monoid M']
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/-- The action by a submonoid is the action by the underlying monoid. -/
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@[to_additive
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"The additive action by an `AddSubmonoid` is the action by the underlying `AddMonoid`. "]
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instance mulAction [MulAction M' α] (S : Submonoid M') : MulAction S α :=
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MulAction.compHom _ S.subtype
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example {S : Submonoid M'} : IsScalarTower S M' M' := by infer_instance
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end Submonoid
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end Actions
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section Units
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namespace Submonoid

‎Mathlib/Algebra/Module/Submodule/Defs.lean

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-/
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import Mathlib.Algebra.Group.Subgroup.Defs
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import Mathlib.GroupTheory.GroupAction.SubMulAction
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import Mathlib.Algebra.Group.Submonoid.Basic
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/-!
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‎Mathlib/Algebra/Polynomial/Basic.lean

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import Mathlib.Algebra.Order.Monoid.Unbundled.WithTop
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import Mathlib.Data.Finset.Sort
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import Mathlib.Tactic.FastInstance
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import Mathlib.Algebra.Group.Submonoid.Operations
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/-!
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# Theory of univariate polynomials

‎Mathlib/GroupTheory/GroupAction/Defs.lean

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-/
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import Mathlib.Algebra.Group.Pointwise.Set.Basic
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import Mathlib.Algebra.Group.Subgroup.Defs
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import Mathlib.Algebra.Group.Submonoid.Operations
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import Mathlib.Algebra.GroupWithZero.Action.Defs
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import Mathlib.Algebra.Group.Submonoid.MulAction
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/-!
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# Definition of `orbit`, `fixedPoints` and `stabilizer`

‎Mathlib/GroupTheory/MonoidLocalization/Basic.lean

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import Mathlib.Algebra.Group.Submonoid.Defs
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import Mathlib.GroupTheory.Congruence.Hom
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import Mathlib.GroupTheory.OreLocalization.Basic
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import Mathlib.Algebra.Group.Submonoid.Operations
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/-!
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# Localizations of commutative monoids

‎Mathlib/GroupTheory/OreLocalization/Basic.lean

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Released under Apache 2.0 license as described in the file LICENSE.
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Authors: Jakob von Raumer, Kevin Klinge, Andrew Yang
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-/
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import Mathlib.Algebra.Group.Submonoid.Operations
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import Mathlib.GroupTheory.OreLocalization.OreSet
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import Mathlib.Tactic.Common
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import Mathlib.Algebra.Group.Submonoid.MulAction
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import Mathlib.Algebra.Group.Units.Defs
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/-!
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‎Mathlib/Topology/Algebra/Monoid.lean

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import Mathlib.Algebra.BigOperators.Pi
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import Mathlib.Algebra.Group.ULift
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import Mathlib.Topology.ContinuousMap.Defs
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import Mathlib.Algebra.Group.Submonoid.Basic
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/-!
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# Theory of topological monoids

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