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Description: Version of nfsb2 with a disjoint variable condition, which does not require ax-13 , and removal of ax-13 from nfs1v . (Contributed by BJ, 24-Jun-2019) (Proof modification is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | bj-nfs1v | ⊢ Ⅎ 𝑥 [ 𝑦 / 𝑥 ] 𝜑 |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | bj-hbs1 | ⊢ ( [ 𝑦 / 𝑥 ] 𝜑 → ∀ 𝑥 [ 𝑦 / 𝑥 ] 𝜑 ) | |
| 2 | 1 | nf5i | ⊢ Ⅎ 𝑥 [ 𝑦 / 𝑥 ] 𝜑 |