8b0cca57d1
This commit fixes issue #1631. However, it is not a perfect solution. This commit improves the predicate that checks whether a definition is noncomputable or not. This predicate was implemented before we had a code generator. We should refactor the code and use the code generator to check whether a definition is noncomputable or not. Otherwise, we will keep finding mismatches between the predicate at noncomputable.cpp and what the code generator implements.
37 lines
1.8 KiB
Text
37 lines
1.8 KiB
Text
constant bag_setoid : ∀ A, setoid (list A)
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attribute [instance] bag_setoid
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definition bag (A : Type) : Type :=
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quotient (bag_setoid A)
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constant subcount : ∀ {A}, list A → list A → bool
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constant list.count : ∀ {A}, A → list A → nat
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constant all_of_subcount_eq_tt : ∀ {A} {l₁ l₂ : list A}, subcount l₁ l₂ = tt → ∀ a, list.count a l₁ ≤ list.count a l₂
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constant ex_of_subcount_eq_ff : ∀ {A} {l₁ l₂ : list A}, subcount l₁ l₂ = ff → ∃ a, ¬ list.count a l₁ ≤ list.count a l₂
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noncomputable definition count {A} (a : A) (b : bag A) : nat :=
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quotient.lift_on b (λ l, list.count a l)
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(λ l₁ l₂ h, sorry)
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definition subbag {A} (b₁ b₂ : bag A) := ∀ a, count a b₁ ≤ count a b₂
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infix ⊆ := subbag
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noncomputable definition decidable_subbag_1 {A} (b₁ b₂ : bag A) : decidable (b₁ ⊆ b₂) :=
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quotient.rec_on_subsingleton₂ b₁ b₂ (λ l₁ l₂,
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match subcount l₁ l₂, rfl : ∀ (b : _), subcount l₁ l₂ = b → _ with
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| tt, H := is_true (all_of_subcount_eq_tt H)
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| ff, H := is_false (λ h, exists.elim (ex_of_subcount_eq_ff H) (λ w hw, _))
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end)
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noncomputable definition decidable_subbag_2 {A} (b₁ b₂ : bag A) : decidable (b₁ ⊆ b₂) :=
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quotient.rec_on_subsingleton₂ b₁ b₂ (λ l₁ l₂,
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match subcount l₁ l₂, rfl : ∀ (b : _), subcount l₁ l₂ = b → _ with
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| tt, H := is_true (all_of_subcount_eq_tt H)
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| ff, H := is_false (λ h, exists.elim (ex_of_subcount_eq_ff H) _)
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end)
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noncomputable definition decidable_subbag_3 {A} (b₁ b₂ : bag A) : decidable (b₁ ⊆ b₂) :=
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quotient.rec_on_subsingleton₂ b₁ b₂ (λ l₁ l₂,
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match subcount l₁ l₂, rfl : ∀ (b : _), subcount l₁ l₂ = b → _ with
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| tt, H := is_true (all_of_subcount_eq_tt H)
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| ff, H := is_false (λ h, _)
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end)
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