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Theorem frege61c 44868
Description: Lemma for frege65c 44872. Proposition 61 of [Frege1879] p. 52. (Contributed by RP, 24-Dec-2019.) (Proof modification is discouraged.)
Hypothesis
Ref Expression
frege59c.a 𝐴 ∈ 𝐵
Assertion
Ref Expression
frege61c (([𝐴 / 𝑥]𝜑 → 𝜓) → (∀𝑥𝜑 → 𝜓))

Proof of Theorem frege61c
StepHypRef Expression
1 frege59c.a . . 3 𝐴 ∈ 𝐵
21frege58c 44865 . 2 (∀𝑥𝜑 → [𝐴 / 𝑥]𝜑)
3 frege9 44756 . 2 ((∀𝑥𝜑 → [𝐴 / 𝑥]𝜑) → (([𝐴 / 𝑥]𝜑 → 𝜓) → (∀𝑥𝜑 → 𝜓)))
42, 3ax-mp 5 1 (([𝐴 / 𝑥]𝜑 → 𝜓) → (∀𝑥𝜑 → 𝜓))
Colors of variables:    wff setvar class
This proof depends on syntax axioms:   → wi 4  ∀wal 1568   ∈ wcel 2145  [wsbc 3738
This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-8 2147  ax-9 2155  ax-ext 2732  ax-frege1 44734  ax-frege2 44735  ax-frege8 44753  ax-frege58b 44845
This proof depends on definitions:  df-bi 210  df-an 402  df-tru 1573  df-ex 1813  df-sb 2100  df-clab 2739  df-cleq 2752  df-clel 2835  df-sbc 3739
This theorem is used by:  frege65c  44872
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