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Theorem cbv3h 1647
Description: Rule used to change bound variables, using implicit substitution. (Contributed by NM, 5-Aug-1993.) (Proof shortened by Andrew Salmon, 25-May-2011.) (Proof shortened by Wolf Lammen, 12-May-2018.)
Hypotheses
Ref Expression
cbv3h.1 (𝜑 → ∀𝑦𝜑)
cbv3h.2 (𝜓 → ∀𝑥𝜓)
cbv3h.3 (𝑥 = 𝑦 → (𝜑𝜓))
Assertion
Ref Expression
cbv3h (∀𝑥𝜑 → ∀𝑦𝜓)

Proof of Theorem cbv3h
StepHypRef Expression
1 cbv3h.1 . . 3 (𝜑 → ∀𝑦𝜑)
21nfi 1367 . 2 𝑦𝜑
3 cbv3h.2 . . 3 (𝜓 → ∀𝑥𝜓)
43nfi 1367 . 2 𝑥𝜓
5 cbv3h.3 . 2 (𝑥 = 𝑦 → (𝜑𝜓))
62, 4, 5cbv3 1646 1 (∀𝑥𝜑 → ∀𝑦𝜓)
Colors of variables: wff set class
Syntax hints:  wi 4  wal 1257
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 103  ax-ia2 104  ax-ia3 105  ax-5 1352  ax-7 1353  ax-gen 1354  ax-ie1 1398  ax-ie2 1399  ax-4 1416  ax-i9 1439  ax-ial 1443
This theorem depends on definitions:  df-bi 114  df-nf 1366
This theorem is referenced by:  cbvalh  1652  ax16  1710  ax16i  1754  cleqh  2153
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