Skip to content

Commit

Permalink
some facts and a fact with a gap
Browse files Browse the repository at this point in the history
  • Loading branch information
martinescardo committed Sep 20, 2024
1 parent b706b4a commit 2794f01
Show file tree
Hide file tree
Showing 2 changed files with 256 additions and 89 deletions.
12 changes: 6 additions & 6 deletions source/Naturals/RootsTruncation.lagda
Original file line number Diff line number Diff line change
Expand Up @@ -290,16 +290,16 @@ extensionlity.

private
abstract
minimal-pair' : (A : ℕ → 𝓤 ̇ )
minimal-pair : (A : ℕ → 𝓤 ̇ )
→ ((n : ℕ) → A n → (k : ℕ) → k < n → is-decidable (A k))
→ (n : ℕ)
→ A n
→ Σ (k , aₖ) ꞉ Σ A , ((i : ℕ) → A i → k ≤ i)
minimal-pair' A δ 0 a₀ = (0 , a₀) , (λ i aᵢ → zero-least i)
minimal-pair' A δ (succ n) aₙ₊₁ = II
minimal-pair A δ 0 a₀ = (0 , a₀) , (λ i aᵢ → zero-least i)
minimal-pair A δ (succ n) aₙ₊₁ = II
where
IH : Σ (j , aⱼ₊₁) ꞉ Σ (A ∘ succ) , ((i : ℕ) → A (succ i) → j ≤ i)
IH = minimal-pair' (A ∘ succ) (λ n aₙ₊₁ j → δ (succ n) aₙ₊₁ (succ j)) n aₙ₊₁
IH = minimal-pair (A ∘ succ) (λ n aₙ₊₁ j → δ (succ n) aₙ₊₁ (succ j)) n aₙ₊₁

I : type-of IH
→ Σ (k , aₖ) ꞉ Σ A , ((i : ℕ) → A i → k ≤ i)
Expand All @@ -320,7 +320,7 @@ module _ (A : ℕ → 𝓤 ̇ )
where

minimal-pair : Σ A → Σ A
minimal-pair (n , aₙ) = pr₁ (minimal-pair' A δ n aₙ)
minimal-pair (n , aₙ) = pr₁ (minimal-pair A δ n aₙ)

minimal-number : Σ A → ℕ
minimal-number = pr₁ ∘ minimal-pair
Expand All @@ -329,7 +329,7 @@ module _ (A : ℕ → 𝓤 ̇ )
minimal-number-requirement = pr₂ ∘ minimal-pair

minimality : (σ : Σ A) → (i : ℕ) → A i → minimal-number σ ≤ i
minimality (n , aₙ) = pr₂ (minimal-pair' A δ n aₙ)
minimality (n , aₙ) = pr₂ (minimal-pair A δ n aₙ)

minimal-pair-wconstant : is-prop-valued-family A → wconstant minimal-pair
minimal-pair-wconstant A-prop-valued σ σ' =
Expand Down
Loading

0 comments on commit 2794f01

Please sign in to comment.