Prove multi-key access monotonicity in finite maps

Signed-off-by: Danila Fedorin <danila.fedorin@gmail.com>
This commit is contained in:
Danila Fedorin 2024-03-09 13:58:07 -08:00
parent bc138d87f0
commit 0c088ca2ae

View File

@ -2,7 +2,7 @@ open import Lattice
open import Relation.Binary.PropositionalEquality as Eq
using (_≡_;refl; sym; trans; cong; subst)
open import Agda.Primitive using (Level) renaming (_⊔_ to _⊔_)
open import Data.List using (List)
open import Data.List using (List; _∷_; [])
module Lattice.FiniteMap {a b : Level} (A : Set a) (B : Set b)
(_≈₂_ : B B Set b)
@ -10,8 +10,9 @@ module Lattice.FiniteMap {a b : Level} (A : Set a) (B : Set b)
(≡-dec-A : IsDecidable (_≡_ {a} {A}))
(lB : IsLattice B _≈₂_ _⊔₂_ _⊓₂_) where
open IsLattice lB using () renaming (_≼_ to _≼₂_)
open import Lattice.Map A B _≈₂_ _⊔₂_ _⊓₂_ ≡-dec-A lB as Map
using (Map; ⊔-equal-keys; ⊓-equal-keys)
using (Map; ⊔-equal-keys; ⊓-equal-keys; ∈k-dec; m₁≼m₂⇒m₁[k]≼m₂[k])
renaming
( _≈_ to _≈ᵐ_
; _⊔_ to _⊔ᵐ_
@ -28,9 +29,21 @@ open import Lattice.Map A B _≈₂_ _⊔₂_ _⊓₂_ ≡-dec-A lB as Map
; absorb-⊔-⊓ to absorb-⊔ᵐ-⊓ᵐ
; absorb-⊓-⊔ to absorb-⊓ᵐ-⊔ᵐ
; ≈-dec to ≈ᵐ-dec
; _[_] to _[_]ᵐ
; locate to locateᵐ
; keys to keysᵐ
; _updating_via_ to _updatingᵐ_via_
; updating-via-keys-≡ to updatingᵐ-via-keys-≡
; f'-Monotonic to f'-Monotonicᵐ
; _≼_ to _≼ᵐ_
)
open import Data.List.Membership.Propositional using () renaming (_∈_ to _∈ˡ_)
open import Data.Product using (_×_; _,_; Σ; proj₁ ; proj₂)
open import Equivalence
open import Function using (_∘_)
open import Relation.Nullary using (¬_; Dec; yes; no)
open import Utils using (Pairwise; _∷_; [])
open import Data.Empty using (⊥-elim)
module _ (ks : List A) where
FiniteMap : Set (a ⊔ℓ b)
@ -56,6 +69,18 @@ module _ (ks : List A) where
km₁≡ks
)
_∈k_ : A FiniteMap Set a
_∈k_ k (m₁ , _) = k ∈ˡ (keysᵐ m₁)
_updating_via_ : FiniteMap List A (A B) FiniteMap
_updating_via_ (m₁ , ksm₁≡ks) ks f =
( m₁ updatingᵐ ks via f
, trans (sym (updatingᵐ-via-keys-≡ m₁ ks f)) ksm₁≡ks
)
_[_] : FiniteMap List A List B
_[_] (m₁ , _) ks = m₁ [ ks ]ᵐ
≈-equiv : IsEquivalence FiniteMap _≈_
≈-equiv = record
{ ≈-refl =
@ -97,6 +122,8 @@ module _ (ks : List A) where
; absorb-⊓-⊔ = λ (m₁ , _) (m₂ , _) absorb-⊓ᵐ-⊔ᵐ m₁ m₂
}
open IsLattice isLattice using (_≼_) public
lattice : Lattice FiniteMap
lattice = record
{ _≈_ = _≈_
@ -104,3 +131,46 @@ module _ (ks : List A) where
; _⊓_ = _⊓_
; isLattice = isLattice
}
module _ {l} {L : Set l}
{_≈ˡ_ : L L Set l} {_⊔ˡ_ : L L L} {_⊓ˡ_ : L L L}
(lL : IsLattice L _≈ˡ_ _⊔ˡ_ _⊓ˡ_) where
open IsLattice lL using () renaming (_≼_ to _≼ˡ_)
module _ (f : L FiniteMap) (f-Monotonic : Monotonic _≼ˡ_ _≼_ f)
(g : A L B) (g-Monotonicʳ : k Monotonic _≼ˡ_ _≼₂_ (g k))
(ks : List A) where
updater : L A B
updater l k = g k l
f' : L FiniteMap
f' l = (f l) updating ks via (updater l)
f'-Monotonic : Monotonic _≼ˡ_ _≼_ f'
f'-Monotonic {l₁} {l₂} l₁≼l₂ = f'-Monotonicᵐ lL (proj₁ f) f-Monotonic g g-Monotonicʳ ks l₁≼l₂
all-equal-keys : (fm₁ fm₂ : FiniteMap) (Map.keys (proj₁ fm₁) Map.keys (proj₁ fm₂))
all-equal-keys (fm₁ , km₁≡ks) (fm₂ , km₂≡ks) = trans km₁≡ks (sym km₂≡ks)
∈k-exclusive : (fm₁ fm₂ : FiniteMap) {k : A} ¬ ((k ∈k fm₁) × (¬ k ∈k fm₂))
∈k-exclusive fm₁ fm₂ {k} (k∈kfm₁ , k∉kfm₂) =
let
k∈kfm₂ = subst (λ l k ∈ˡ l) (all-equal-keys fm₁ fm₂) k∈kfm₁
in
k∉kfm₂ k∈kfm₂
m₁≼m₂⇒m₁[ks]≼m₂[ks] : (fm₁ fm₂ : FiniteMap) (ks' : List A)
fm₁ fm₂ Pairwise _≼₂_ (fm₁ [ ks' ]) (fm₂ [ ks' ])
m₁≼m₂⇒m₁[ks]≼m₂[ks] _ _ [] _ = []
m₁≼m₂⇒m₁[ks]≼m₂[ks] fm₁@(m₁ , km₁≡ks) fm₂@(m₂ , km₂≡ks) (k ks'') m₁≼m₂
with ∈k-dec k (proj₁ m₁) | ∈k-dec k (proj₁ m₂)
... | yes k∈km₁ | yes k∈km₂ =
let
(v₁ , k,v₁∈m₁) = locateᵐ {m = m₁} k∈km₁
(v₂ , k,v₂∈m₂) = locateᵐ {m = m₂} k∈km₂
in
(m₁≼m₂⇒m₁[k]≼m₂[k] m₁ m₂ m₁≼m₂ k,v₁∈m₁ k,v₂∈m₂) m₁≼m₂⇒m₁[ks]≼m₂[ks] fm₁ fm₂ ks'' m₁≼m₂
... | no k∉km₁ | no k∉km₂ = m₁≼m₂⇒m₁[ks]≼m₂[ks] fm₁ fm₂ ks'' m₁≼m₂
... | yes k∈km₁ | no k∉km₂ = ⊥-elim (∈k-exclusive fm₁ fm₂ (k∈km₁ , k∉km₂))
... | no k∉km₁ | yes k∈km₂ = ⊥-elim (∈k-exclusive fm₂ fm₁ (k∈km₂ , k∉km₁))