Documentation

Mathlib.Data.Set.Opposite

The opposite of a set #

The opposite of a set s is simply the set obtained by taking the opposite of each member of s.

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def Set.op {α : Type u_1} (s : Set α) :
Set αᵒᵖ

The opposite of a set s is the set obtained by taking the opposite of each member of s.

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    def Set.unop {α : Type u_1} (s : Set αᵒᵖ) :
    Set α

    The unop of a set s is the set obtained by taking the unop of each member of s.

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    Instances For
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      @[simp]
      theorem Set.mem_op {α : Type u_1} {s : Set α} {a : αᵒᵖ} :
      a ∈ Set.op s ↔ a.unop ∈ s
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      @[simp]
      theorem Set.op_mem_op {α : Type u_1} {s : Set α} {a : α} :
      Opposite.op a ∈ Set.op s ↔ a ∈ s
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      @[simp]
      theorem Set.mem_unop {α : Type u_1} {s : Set αᵒᵖ} {a : α} :
      a ∈ Set.unop s ↔ Opposite.op a ∈ s
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      @[simp]
      theorem Set.unop_mem_unop {α : Type u_1} {s : Set αᵒᵖ} {a : αᵒᵖ} :
      a.unop ∈ Set.unop s ↔ a ∈ s
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      @[simp]
      theorem Set.op_unop {α : Type u_1} (s : Set α) :
      Set.unop (Set.op s) = s
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      @[simp]
      theorem Set.unop_op {α : Type u_1} (s : Set αᵒᵖ) :
      Set.op (Set.unop s) = s
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      @[simp]
      theorem Set.opEquiv_self_symm_apply_coe {α : Type u_1} (s : Set α) (x : ↑s) :
      ↑((Set.opEquiv_self s).symm x) = Opposite.op ↑x
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      @[simp]
      theorem Set.opEquiv_self_apply_coe {α : Type u_1} (s : Set α) (x : ↑(Set.op s)) :
      ↑((Set.opEquiv_self s) x) = (↑x).unop
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      def Set.opEquiv_self {α : Type u_1} (s : Set α) :
      ↑(Set.op s) ≃ ↑s

      The members of the opposite of a set are in bijection with the members of the set itself.

      Equations
      • One or more equations did not get rendered due to their size.
      Instances For
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        @[simp]
        theorem Set.opEquiv_apply {α : Type u_1} (s : Set α) :
        Set.opEquiv s = Set.op s
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        @[simp]
        theorem Set.opEquiv_symm_apply {α : Type u_1} (s : Set αᵒᵖ) :
        Set.opEquiv.symm s = Set.unop s
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        def Set.opEquiv {α : Type u_1} :
        Set α ≃ Set αᵒᵖ

        Taking opposites as an equivalence of powersets.

        Equations
        • Set.opEquiv = { toFun := Set.op, invFun := Set.unop, left_inv := ⋯, right_inv := ⋯ }
        Instances For
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          @[simp]
          theorem Set.singleton_op {α : Type u_1} (x : α) :
          Set.op {x} = {Opposite.op x}
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          @[simp]
          theorem Set.singleton_unop {α : Type u_1} (x : αᵒᵖ) :
          Set.unop {x} = {x.unop}
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          @[simp]
          theorem Set.singleton_op_unop {α : Type u_1} (x : α) :
          Set.unop {Opposite.op x} = {x}
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          @[simp]
          theorem Set.singleton_unop_op {α : Type u_1} (x : αᵒᵖ) :
          Set.op {x.unop} = {x}