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Theorem 2albidv 1763
Description: Formula-building rule for 2 existential quantifiers (deduction rule). (Contributed by NM, 4-Mar-1997.)
Hypothesis
Ref Expression
2albidv.1 (𝜑 → (𝜓𝜒))
Assertion
Ref Expression
2albidv (𝜑 → (∀𝑥𝑦𝜓 ↔ ∀𝑥𝑦𝜒))
Distinct variable groups:   𝜑,𝑥   𝜑,𝑦
Allowed substitution hints:   𝜓(𝑥,𝑦)   𝜒(𝑥,𝑦)

Proof of Theorem 2albidv
StepHypRef Expression
1 2albidv.1 . . 3 (𝜑 → (𝜓𝜒))
21albidv 1721 . 2 (𝜑 → (∀𝑦𝜓 ↔ ∀𝑦𝜒))
32albidv 1721 1 (𝜑 → (∀𝑥𝑦𝜓 ↔ ∀𝑥𝑦𝜒))
Colors of variables: wff set class
Syntax hints:  wi 4  wb 102  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-gen 1354  ax-17 1435
This theorem depends on definitions:  df-bi 114
This theorem is referenced by:  dff13  5435  qliftfun  6219
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