Mercurial > hg > Members > kono > Proof > ZF-in-agda
diff ordinal.agda @ 236:650bdad56729
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author | Shinji KONO <kono@ie.u-ryukyu.ac.jp> |
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date | Fri, 16 Aug 2019 15:53:29 +0900 |
parents | e06b76e5b682 |
children | c10048d69614 |
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--- a/ordinal.agda Thu Aug 15 04:51:24 2019 +0900 +++ b/ordinal.agda Fri Aug 16 15:53:29 2019 +0900 @@ -204,21 +204,6 @@ lemma y lt | case1 refl = proj1 ( TransFinite1 lx ox ) lemma y lt | case2 lt1 = proj2 ( TransFinite1 lx ox ) y lt1 --- we cannot prove this in intutionistic logic --- (¬ (∀ y → ¬ ( ψ y ))) → (ψ y → p ) → p --- postulate --- TransFiniteExists : {n m l : Level} → ( ψ : Ordinal {n} → Set m ) --- → (exists : ¬ (∀ y → ¬ ( ψ y ) )) --- → {p : Set l} ( P : { y : Ordinal {n} } → ψ y → p ) --- → p --- --- Instead we prove --- -TransFiniteExists : {n m l : Level} → ( ψ : Ordinal {n} → Set m ) - → {p : Set l} ( P : { y : Ordinal {n} } → ψ y → ¬ p ) - → (exists : ¬ (∀ y → ¬ ( ψ y ) )) - → ¬ p -TransFiniteExists {n} {m} {l} ψ {p} P = contra-position ( λ p y ψy → P {y} ψy p ) open import Ordinals