Step
*
of Lemma
second-countable-choice
∀[X:𝕌']. ∀[R:ℕ ⟶ (n:ℕ ⟶ (ℕn ⟶ ℕ) ⟶ X) ⟶ ℙ'].
((∀n:ℕ. ∃A:n:ℕ ⟶ (ℕn ⟶ ℕ) ⟶ X. R[n;A])
⇒ (∃B:n:ℕ ⟶ (ℕn ⟶ ℕ) ⟶ X. ∀n:ℕ. R[n;B_n]))
BY
{ (Auto THEN (Skolemize (-1) `f' THENA Auto)) }
1
1. [X] : 𝕌'
2. [R] : ℕ ⟶ (n:ℕ ⟶ (ℕn ⟶ ℕ) ⟶ X) ⟶ ℙ'
3. ∀n:ℕ. ∃A:n:ℕ ⟶ (ℕn ⟶ ℕ) ⟶ X. R[n;A]
4. f : n:ℕ ⟶ n:ℕ ⟶ (ℕn ⟶ ℕ) ⟶ X
5. ∀n:ℕ. R[n;f n]
⊢ ∃B:n:ℕ ⟶ (ℕn ⟶ ℕ) ⟶ X. ∀n:ℕ. R[n;B_n]
Latex:
Latex:
\mforall{}[X:\mBbbU{}']. \mforall{}[R:\mBbbN{} {}\mrightarrow{} (n:\mBbbN{} {}\mrightarrow{} (\mBbbN{}n {}\mrightarrow{} \mBbbN{}) {}\mrightarrow{} X) {}\mrightarrow{} \mBbbP{}'].
((\mforall{}n:\mBbbN{}. \mexists{}A:n:\mBbbN{} {}\mrightarrow{} (\mBbbN{}n {}\mrightarrow{} \mBbbN{}) {}\mrightarrow{} X. R[n;A]) {}\mRightarrow{} (\mexists{}B:n:\mBbbN{} {}\mrightarrow{} (\mBbbN{}n {}\mrightarrow{} \mBbbN{}) {}\mrightarrow{} X. \mforall{}n:\mBbbN{}. R[n;B\_n]))
By
Latex:
(Auto THEN (Skolemize (-1) `f' THENA Auto))
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