23 lines
727 B
Text
23 lines
727 B
Text
/-
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Copyright (c) 2014 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Author: Leonardo de Moura, Jeremy Avigad, Floris van Doorn
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-/
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prelude
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import init.datatypes init.num init.wf init.logic
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definition dpair := @sigma.mk
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notation `Σ` binders `, ` r:(scoped P, sigma P) := r
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universe variables u v
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lemma ex_of_sig {A : Type u} {P : A → Prop} : (Σ x, P x) → ∃ x, P x
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| ⟨x, hx⟩ := ⟨x, hx⟩
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namespace sigma
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variables {A : Type u} {B : A → Type v}
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protected theorem eq : ∀ {p₁ p₂ : Σ a : A, B a} (H₁ : p₁.1 = p₂.1), (eq.rec_on H₁ p₁.2 : B p₂.1) = p₂.2 → p₁ = p₂
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| ⟨a, b⟩ ⟨.a, .b⟩ rfl rfl := rfl
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end sigma
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