Mercurial > hg > Members > kono > Proof > ZF-in-agda
diff zf.agda @ 288:4fcac1eebc74 release
axiom of choice clean up
author | Shinji KONO <kono@ie.u-ryukyu.ac.jp> |
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date | Sun, 07 Jun 2020 20:31:30 +0900 |
parents | 6f10c47e4e7a |
children | fbabb20f222e |
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--- a/zf.agda Thu Aug 29 16:18:37 2019 +0900 +++ b/zf.agda Sun Jun 07 20:31:30 2020 +0900 @@ -19,7 +19,7 @@ (Select : (X : ZFSet ) → ( ψ : (x : ZFSet ) → Set m ) → ZFSet ) (Replace : ZFSet → ( ZFSet → ZFSet ) → ZFSet ) (infinite : ZFSet) - : Set (suc (n ⊔ m)) where + : Set (suc (n ⊔ suc m)) where field isEquivalence : IsEquivalence {n} {m} {ZFSet} _≈_ -- ∀ x ∀ y ∃ z ∀ t ( z ∋ t → t ≈ x ∨ t ≈ y) @@ -35,7 +35,7 @@ _∩_ : ( A B : ZFSet ) → ZFSet A ∩ B = Select A ( λ x → ( A ∋ x ) ∧ ( B ∋ x ) ) _∪_ : ( A B : ZFSet ) → ZFSet - A ∪ B = Union (A , B) -- Select A ( λ x → ( A ∋ x ) ∨ ( B ∋ x ) ) is easier + A ∪ B = Union (A , B) {_} : ZFSet → ZFSet { x } = ( x , x ) infixr 200 _∈_ @@ -48,14 +48,10 @@ power← : ∀( A t : ZFSet ) → ( ∀ {x} → _⊆_ t A {x}) → Power A ∋ t -- extensionality : ∀ z ( z ∈ x ⇔ z ∈ y ) ⇒ ∀ w ( x ∈ w ⇔ y ∈ w ) extensionality : { A B w : ZFSet } → ( (z : ZFSet) → ( A ∋ z ) ⇔ (B ∋ z) ) → ( A ∈ w ⇔ B ∈ w ) - -- This form of regurality forces choice function - -- regularity : ∀ x ( x ≠ ∅ → ∃ y ∈ x ( y ∩ x = ∅ ) ) - -- minimul : (x : ZFSet ) → ¬ (x ≈ ∅) → ZFSet - -- regularity : ∀( x : ZFSet ) → (not : ¬ (x ≈ ∅)) → ( minimul x not ∈ x ∧ ( minimul x not ∩ x ≈ ∅ ) ) - -- another form of regularity - -- ε-induction : { ψ : ZFSet → Set m} - -- → ( {x : ZFSet } → ({ y : ZFSet } → x ∋ y → ψ y ) → ψ x ) - -- → (x : ZFSet ) → ψ x + -- regularity without minimum + ε-induction : { ψ : ZFSet → Set (suc m)} + → ( {x : ZFSet } → ({ y : ZFSet } → x ∋ y → ψ y ) → ψ x ) + → (x : ZFSet ) → ψ x -- infinity : ∃ A ( ∅ ∈ A ∧ ∀ x ∈ A ( x ∪ { x } ∈ A ) ) infinity∅ : ∅ ∈ infinite infinity : ∀( x : ZFSet ) → x ∈ infinite → ( x ∪ { x }) ∈ infinite @@ -63,11 +59,8 @@ -- replacement : ∀ x ∀ y ∀ z ( ( ψ ( x , y ) ∧ ψ ( x , z ) ) → y = z ) → ∀ X ∃ A ∀ y ( y ∈ A ↔ ∃ x ∈ X ψ ( x , y ) ) replacement← : {ψ : ZFSet → ZFSet} → ∀ ( X x : ZFSet ) → x ∈ X → ψ x ∈ Replace X ψ replacement→ : {ψ : ZFSet → ZFSet} → ∀ ( X x : ZFSet ) → ( lt : x ∈ Replace X ψ ) → ¬ ( ∀ (y : ZFSet) → ¬ ( x ≈ ψ y ) ) - -- ∀ X [ ∅ ∉ X → (∃ f : X → ⋃ X ) → ∀ A ∈ X ( f ( A ) ∈ A ) ] - choice-func : (X : ZFSet ) → {x : ZFSet } → ¬ ( x ≈ ∅ ) → ( X ∋ x ) → ZFSet - choice : (X : ZFSet ) → {A : ZFSet } → ( X∋A : X ∋ A ) → (not : ¬ ( A ≈ ∅ )) → A ∋ choice-func X not X∋A -record ZF {n m : Level } : Set (suc (n ⊔ m)) where +record ZF {n m : Level } : Set (suc (n ⊔ suc m)) where infixr 210 _,_ infixl 200 _∋_ infixr 220 _≈_