Mercurial > hg > Members > kono > Proof > ZF-in-agda
diff zf-in-agda.ind @ 361:4cbcf71b09c4
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author | Shinji KONO <kono@ie.u-ryukyu.ac.jp> |
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date | Fri, 17 Jul 2020 16:33:30 +0900 |
parents | 5e22b23ee3fd |
children | aad9249d1e8f |
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--- a/zf-in-agda.ind Wed Jul 15 08:42:30 2020 +0900 +++ b/zf-in-agda.ind Fri Jul 17 16:33:30 2020 +0900 @@ -671,7 +671,7 @@ Agda Set / Type / it also has a level ---Fixes on ZF to intuitionistic logic +--Fixing ZF axom to fit intuitionistic logic We use ODs as Sets in ZF, and defines record ZF, that is, we have to define ZF axioms in Agda. @@ -854,6 +854,21 @@ So what is the bound of ω? Analyzing the definition, it depends on the value of od→ord (x , x), which cannot know the aboslute value. This is because we don't have constructive definition of od→ord : HOD → Ordinal. +--HOD Ordrinal mapping + +We have large freedom on HOD. We reqest no minimality on odmax, so it may arbitrary larger. +The address of HOD can be larger at least it have to be larger than the content's address. +We only have a relative ordering such as + + pair-xx<xy : {x y : HOD} → od→ord (x , x) o< osuc (od→ord (x , y) ) + pair<y : {x y : HOD } → y ∋ x → od→ord (x , x) o< osuc (od→ord y) + +Basicaly, we cannot know the concrete address of HOD other than empty set. + +<center><img src="fig/address-of-HOD.svg"></center> + +--Possible restriction on HOD + We need some restriction on the HOD-Ordinal mapping. Simple one is this. ωmax : Ordinal @@ -872,20 +887,15 @@ --increment pase of address of HOD -The address of HOD may have obvious bound, but it is defined in a relative way. - - pair-xx<xy : {x y : HOD} → od→ord (x , x) o< osuc (od→ord (x , y) ) - pair<y : {x y : HOD } → y ∋ x → od→ord (x , x) o< osuc (od→ord y) - -Basicaly, we cannot know the concrete address of HOD other than empty set. - -Assuming, previous assuption, we have +Assuming, hod-ord< , we have pair-ord< : {x : HOD } → ( {y : HOD } → od→ord y o< next (odmax y) ) → od→ord ( x , x ) o< next (od→ord x) pair-ord< {x} ho< = subst (λ k → od→ord (x , x) o< k ) lemmab0 lemmab1 where lemmab0 : next (odmax (x , x)) ≡ next (od→ord x) -So the address of ( x , x) and Union (x , (x , x)) is restricted in the limit ordinal. This makes ω bound. +So the address of ( x , x) and Union (x , (x , x)) is restricted in the limit ordinal. This makes ω bound. We can prove + + infinite-bound : ({x : HOD} → od→ord x o< next (odmax x)) → {y : Ordinal} → infinite-d y → y o< next o∅ We also notice that if we have od→ord (x , x) ≡ osuc (od→ord x), c<→o< can be drived from ⊆→o≤ .