31 lines
1.3 KiB
Text
31 lines
1.3 KiB
Text
import hott
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open path
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set_option pp.beta true
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variables {A : Type} {B : A → Type} {C : Π a : A, B a → Type} {D : Π (a : A) (b : B a), C a b → Type}
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structure foo :=
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mk :: (a : A) (b : B a) (c : C a b)
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set_option unifier.max_steps 50000
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definition foo.eq {a₁ a₂ : A} {b₁ : B a₁} {b₂ : B a₂} {c₁ : C a₁ b₁} {c₂ : C a₂ b₂}
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(H₁ : a₁ ≈ a₂)
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(H₂ : path.rec_on H₁ b₁ ≈ b₂)
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(H₃ : path.rec_on H₂ (path.rec_on H₁ c₁) ≈ c₂)
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: foo.mk a₁ b₁ c₁ ≈ foo.mk a₂ b₂ c₂ :=
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have aux₁: Π (b₂ : B a₁) (c₂ : C a₁ b₂)
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(H₂ : path.rec_on idp b₁ ≈ b₂)
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(H₃ : path.rec_on H₂ (path.rec_on idp c₁) ≈ c₂),
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foo.mk a₁ b₁ c₁ ≈ foo.mk a₁ b₂ c₂, from
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λ (b₂ : B a₁) (c₂ : C a₁ b₂)
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(H₂ : b₁ ≈ b₂) (H₃ : path.rec_on H₂ c₁ ≈ c₂),
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have aux₂ : Π (c₂ : C a₁ b₁) (H₃ : path.rec_on idp c₁ ≈ c₂),
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foo.mk a₁ b₁ c₁ ≈ foo.mk a₁ b₁ c₂, from
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λ (c₂ : C a₁ b₁) (H₃ : c₁ ≈ c₂),
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have aux₃ : foo.mk a₁ b₁ c₁ ≈ foo.mk a₁ b₁ c₁, from
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idp,
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path.rec_on H₃ aux₃,
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path.rec_on H₂ aux₂ c₂ H₃,
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path.rec_on H₁ aux₁ b₂ c₂ H₂ H₃
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