UFD progress (#108)

This commit is contained in:
Patrick Stevens
2020-04-10 09:24:53 +01:00
committed by GitHub
parent f5bac0c091
commit 1cff95c652
7 changed files with 152 additions and 13 deletions

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@@ -81,7 +81,7 @@ open import Rings.Subrings.Definition
open import Rings.Ideals.Maximal.Lemmas
open import Rings.Primes.Lemmas
open import Rings.Irreducibles.Definition
open import Rings.Divisible.Definition
open import Rings.Divisible.Lemmas
open import Rings.Associates.Lemmas
open import Rings.InitialRing
open import Rings.Homomorphisms.Lemmas

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@@ -6,7 +6,6 @@ open import Functions
open import Sets.EquivalenceRelations
open import Rings.Definition
module Rings.Divisible.Definition {a b : _} {A : Set a} {S : Setoid {a} {b} A} {_+_ _*_ : A A A} (R : Ring S _+_ _*_) where
open Setoid S

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@@ -0,0 +1,30 @@
{-# OPTIONS --safe --warning=error --without-K #-}
open import LogicalFormulae
open import Setoids.Setoids
open import Functions
open import Sets.EquivalenceRelations
open import Rings.Definition
module Rings.Divisible.Lemmas {a b : _} {A : Set a} {S : Setoid {a} {b} A} {_+_ _*_ : A A A} (R : Ring S _+_ _*_) where
open Setoid S
open Equivalence eq
open Ring R
open import Rings.Divisible.Definition R
open import Rings.Units.Definition R
divisionTransitive : (x y z : A) x y y z x z
divisionTransitive x y z (a , pr) (b , pr2) = (a * b) , transitive (transitive *Associative (*WellDefined pr reflexive)) pr2
divisionReflexive : (x : A) x x
divisionReflexive x = 1R , transitive *Commutative identIsIdent
everythingDividesZero : (r : A) r 0R
everythingDividesZero r = 0R , timesZero
nonzeroInherits : {x y : A} (nz : (x 0R) False) y x (y 0R) False
nonzeroInherits {x} {y} nz (c , pr) y=0 = nz (transitive (symmetric pr) (transitive (*WellDefined y=0 reflexive) (transitive *Commutative timesZero)))
nonunitInherits : {x y : A} (nonunit : Unit x False) x y Unit y False
nonunitInherits nu (s , pr) (a , b) = nu ((s * a) , transitive (transitive *Associative (*WellDefined pr reflexive)) b)

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@@ -6,7 +6,6 @@ open import Sets.EquivalenceRelations
open import Rings.IntegralDomains.Definition
open import Rings.Definition
module Rings.Irreducibles.Lemmas {a b : _} {A : Set a} {S : Setoid {a} {b} A} {_+_ _*_ : A A A} {R : Ring S _+_ _*_} (intDom : IntegralDomain R) where
open import Rings.Irreducibles.Definition intDom

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@@ -4,7 +4,10 @@ open import LogicalFormulae
open import Setoids.Setoids
open import Rings.Definition
open import Rings.IntegralDomains.Definition
open import Lists.Lists
open import Vectors
open import Numbers.Naturals.Semiring
open import Numbers.Naturals.Order
open import Numbers.Naturals.Definition
open import Agda.Primitive using (Level; lzero; lsuc; _⊔_)
@@ -12,16 +15,44 @@ module Rings.UniqueFactorisationDomains.Definition {a b : _} {A : Set a} {S : Se
open import Rings.Units.Definition R
open import Rings.Irreducibles.Definition intDom
open import Rings.Associates.Definition intDom
open import Rings.Primes.Definition intDom
open Ring R
open Setoid S
record Factorisation {r : A} (nonzero : (r 0R) False) (nonunit : (Unit r) False) : Set (a b) where
field
factorise : List A
factoriseIsFactorisation : fold (_*_) 1R factorise r
factoriseIsIrreducibles : allTrue Irreducible factorise
private
power : A A
power x zero = 1R
power x (succ n) = x * power x n
--record UFD : Set (a ⊔ b) where
-- field
-- factorisation : {r : A} → (nonzero : (r 0R) → False) → (nonunit : (Unit r) → False) → Factorisation nonzero nonunit
-- uniqueFactorisation : {r : A} → (nonzero : (r 0R) → False) → (nonunit : (Unit r) → False) → (f1 f2 : Factorisation nonzero nonunit) → {!Sg !}
allDistinct : {n : } Vec A n Set (a b)
allDistinct [] = True'
allDistinct (x ,- xs) = (allDistinct xs) && vecAllTrue (λ n (n x) False) xs
record Factorisation {r : A} .(nonzero : (r 0R) False) .(nonunit : (Unit r) False) : Set (a b) where
field
len :
factorise : Vec (A && ) len
factoriseIsFactorisation : vecFold (λ x y y * power (_&&_.fst x) (succ (_&&_.snd x))) 1R factorise r
factoriseIsIrreducibles : vecAllTrue Irreducible (vecMap _&&_.fst factorise)
distinct : allDistinct (vecMap _&&_.fst factorise)
private
equality : {n : } (v1 v2 : Vec (A && ) n) Set (a b)
equality [] [] = True'
equality {succ n} ((a ,, an) ,- v1) v2 = Sg (λ index Sg (index <N succ n) (λ i<n (Associates (_&&_.fst (vecIndex v2 index i<n)) a) && ((_&&_.snd (vecIndex v2 index i<n) an) && equality v1 (vecDelete index i<n v2))))
factorisationEquality : {r : A} .{nonzero : (r 0R) False} .{nonunit : (Unit r) False} Factorisation nonzero nonunit Factorisation nonzero nonunit Set (a b)
factorisationEquality record { len = lenA ; factorise = factoriseA ; factoriseIsFactorisation = factoriseIsFactorisationA ; factoriseIsIrreducibles = factoriseIsIrreduciblesA ; distinct = distinctA } record { len = lenB ; factorise = factoriseB ; factoriseIsFactorisation = factoriseIsFactorisationB ; factoriseIsIrreducibles = factoriseIsIrreduciblesB ; distinct = distinctB } with DecideEquality lenA lenB
factorisationEquality record { len = a ; factorise = factoriseA } record { len = .a ; factorise = factoriseB } | inl refl = equality factoriseA factoriseB
factorisationEquality record { len = a ; factorise = factoriseA } record { len = b ; factorise = factoriseB } | inr _ = False'
record UFD : Set (a b) where
field
factorisation : {r : A} (nonzero : (r 0R) False) (nonunit : (Unit r) False) Factorisation nonzero nonunit
uniqueFactorisation : {r : A} (nonzero : (r 0R) False) (nonunit : (Unit r) False) (f1 f2 : Factorisation nonzero nonunit) factorisationEquality f1 f2
record UFD' : Set (a b) where
field
factorisation : {r : A} (nonzero : (r 0R) False) (nonunit : (Unit r) False) Factorisation nonzero nonunit
irreduciblesArePrime : {r : A} Irreducible r Prime r

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@@ -0,0 +1,57 @@
{-# OPTIONS --safe --warning=error --without-K #-}
open import LogicalFormulae
open import Setoids.Setoids
open import Rings.Definition
open import Rings.IntegralDomains.Definition
open import Vectors
open import Numbers.Naturals.Semiring
open import Numbers.Naturals.Order
open import Numbers.Naturals.Definition
open import Sets.EquivalenceRelations
open import Agda.Primitive using (Level; lzero; lsuc; _⊔_)
module Rings.UniqueFactorisationDomains.Lemmas {a b : _} {A : Set a} {S : Setoid {a} {b} A} {_+_ _*_ : A A A} {R : Ring S _+_ _*_} (intDom : IntegralDomain R) where
open import Rings.Units.Definition R
open import Rings.Irreducibles.Definition intDom
open import Rings.Associates.Definition intDom
open import Rings.Primes.Definition intDom
open import Rings.Divisible.Definition R
open import Rings.Divisible.Lemmas R
open import Rings.UniqueFactorisationDomains.Definition intDom
open Ring R
open Setoid S
open Equivalence eq
ufdImpliesUfd' : UFD UFD'
UFD'.factorisation (ufdImpliesUfd' x) = UFD.factorisation x
Prime.isPrime (UFD'.irreduciblesArePrime (ufdImpliesUfd' ufd) {r} irreducible) a b (s , ab=rs) rNotDivA = {!!}
where
-- we can't factorise a, it might be a unit :(
factA : Factorisation {a} (λ p rNotDivA (divisibleWellDefined reflexive (symmetric p) (everythingDividesZero r))) {!!}
factA = UFD.factorisation ufd {a} {!!} {!!}
fact1 : Factorisation {r} {!!} {!!}
fact1 = {!!}
fact2 : Factorisation {r} {!!} {!!}
fact2 = {!!}
Prime.nonzero (UFD'.irreduciblesArePrime (ufdImpliesUfd' x) irreducible) = Irreducible.nonzero irreducible
Prime.nonunit (UFD'.irreduciblesArePrime (ufdImpliesUfd' x) irreducible) = Irreducible.nonunit irreducible
private
lemma2 : UFD' {r : A} .(nonzero : (r 0R) False) .(nonunit : (Unit r) False) (f1 f2 : Factorisation {r} nonzero nonunit) factorisationEquality f1 f2
lemma2 x nonzero nonunit record { len = lenA ; factorise = factoriseA ; factoriseIsFactorisation = factoriseIsFactorisationA ; factoriseIsIrreducibles = factoriseIsIrreduciblesA ; distinct = distinctA } record { len = lenB ; factorise = factoriseB ; factoriseIsFactorisation = factoriseIsFactorisationB ; factoriseIsIrreducibles = factoriseIsIrreduciblesB ; distinct = distinctB } with DecideEquality lenA lenB
lemma2 x nonzero nonunit record { len = zero ; factorise = [] ; factoriseIsFactorisation = factoriseIsFactorisationA ; factoriseIsIrreducibles = factoriseIsIrreduciblesA ; distinct = distinctA } record { len = .0 ; factorise = [] ; factoriseIsFactorisation = factoriseIsFactorisationB ; factoriseIsIrreducibles = factoriseIsIrreduciblesB ; distinct = distinctB } | inl refl = record {}
lemma2 ufd' {r} nonzero nonunit record { len = (succ len) ; factorise = (a1 ,, n1) ,- factoriseA ; factoriseIsFactorisation = factoriseIsFactorisationA ; factoriseIsIrreducibles = factoriseIsIrreduciblesA ; distinct = distinctA } record { len = .(succ len) ; factorise = factoriseB ; factoriseIsFactorisation = factoriseIsFactorisationB ; factoriseIsIrreducibles = factoriseIsIrreduciblesB ; distinct = distinctB } | inl refl = {!!}
where
a1Prime : Prime a1
a1Prime = UFD'.irreduciblesArePrime ufd' (_&&_.fst factoriseIsIrreduciblesA)
a1DivR : a1 r
a1DivR = {!!}
... | inr neq = {!!}
ufd'ImpliesUfd : UFD' UFD
UFD.factorisation (ufd'ImpliesUfd x) = UFD'.factorisation x
UFD.uniqueFactorisation (ufd'ImpliesUfd x) {r} nonzero nonunit f1 f2 = lemma2 x nonzero nonunit f1 f2

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@@ -3,6 +3,7 @@
open import LogicalFormulae
open import Numbers.Naturals.Semiring
open import Numbers.Naturals.Order
open import Numbers.Naturals.Order.Lemmas
open import Semirings.Definition
open import Orders.Total.Definition
open import Lists.Lists
@@ -134,6 +135,28 @@ vecPure : {a : _} {X : Set a} → X → {n : } → Vec X n
vecPure x {zero} = []
vecPure x {succ n} = x ,- vecPure x {n}
vecAllTrue : {a b : _} {X : Set a} (f : X Set b) {n : } (v : Vec X n) Set b
vecAllTrue f [] = True'
vecAllTrue f (x ,- v) = f x && vecAllTrue f v
vecFold : {a b : _} {X : Set a} {S : Set b} (f : X S S) (s : S) {n : } (v : Vec X n) S
vecFold f s [] = s
vecFold f s (x ,- v) = vecFold f (f x s) v
private
succLess1 : (i : ) .(succ i <N 1) False
succLess1 zero pr with <NProp pr
... | le zero ()
... | le (succ x) ()
succLess1 (succ i) pr with <NProp pr
... | le zero ()
... | le (succ x) ()
vecDelete : {a : _} {X : Set a} {n : } (index : ) .(pr : index <N succ n) Vec X (succ n) Vec X n
vecDelete zero _ (x ,- v) = v
vecDelete (succ i) p (x ,- []) = exFalso (succLess1 i p)
vecDelete (succ i) pr (x ,- (y ,- v)) = x ,- vecDelete i (canRemoveSuccFrom<N pr) (y ,- v)
_$V_ : {a b : _} {X : Set a} {Y : Set b} {n : } Vec (X Y) n Vec X n Vec Y n
[] $V [] = []
(f ,- fs) $V (x ,- xs) = f x ,- (fs $V xs)