Mercurial > hg > Members > kono > Proof > ZF-in-agda
diff ordinal.agda @ 339:feb0fcc430a9
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author | Shinji KONO <kono@ie.u-ryukyu.ac.jp> |
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date | Sun, 12 Jul 2020 19:55:37 +0900 |
parents | 0faa7120e4b5 |
children | adc3c3a37308 811152bf2f47 |
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--- a/ordinal.agda Sun Jul 12 12:32:42 2020 +0900 +++ b/ordinal.agda Sun Jul 12 19:55:37 2020 +0900 @@ -226,10 +226,19 @@ } where next : Ordinal {suc n} → Ordinal {suc n} next (ordinal lv ord) = ordinal (Suc lv) (Φ (Suc lv)) - next-limit : {y : Ordinal} → (y o< next y) ∧ ((x : Ordinal) → x o< next y → osuc x o< next y) - next-limit {y} = record { proj1 = case1 a<sa ; proj2 = lemma } where + next-limit : {y : Ordinal} → (y o< next y) ∧ ((x : Ordinal) → x o< next y → osuc x o< next y) ∧ + ( (x : Ordinal) → y o< x → x o< next y → ¬ ((z : Ordinal) → ¬ (x ≡ osuc z) )) + next-limit {y} = record { proj1 = case1 a<sa ; proj2 = record { proj1 = lemma ; proj2 = lemma2 } } where lemma : (x : Ordinal) → x o< next y → osuc x o< next y lemma x (case1 lt) = case1 lt + lemma2 : (x : Ordinal) → y o< x → x o< next y → ¬ ((z : Ordinal) → ¬ x ≡ osuc z) + lemma2 (ordinal Zero (Φ 0)) (case2 ()) (case1 (s≤s z≤n)) not + lemma2 (ordinal Zero (OSuc 0 dx)) (case2 Φ<) (case1 (s≤s z≤n)) not = not _ refl + lemma2 (ordinal Zero (OSuc 0 dx)) (case2 (s< x)) (case1 (s≤s z≤n)) not = not _ refl + lemma2 (ordinal (Suc lx) (OSuc (Suc lx) ox)) y<x (case1 (s≤s (s≤s lt))) not = not _ refl + lemma2 (ordinal (Suc lx) (Φ (Suc lx))) (case1 x) (case1 (s≤s (s≤s lt))) not = lemma3 x lt where + lemma3 : {n l : Nat} → (Suc (Suc n) ≤ Suc l) → l ≤ n → ⊥ + lemma3 (s≤s sn≤l) (s≤s l≤n) = lemma3 sn≤l l≤n not-limit : (x : Ordinal) → Dec (¬ ((y : Ordinal) → ¬ (x ≡ osuc y))) not-limit (ordinal lv (Φ lv)) = no (λ not → not (λ y () )) not-limit (ordinal lv (OSuc lv ox)) = yes (λ not → not (ordinal lv ox) refl )