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Theorem r19.20 1251
Description: Distribution of restricted quantification over implication.
Assertion
Ref Expression
r19.20 (∀xA (φψ) → (∀xA φ → ∀xA ψ))

Proof of Theorem r19.20
StepHypRef Expression
1 df-ral 1205 . . 3 (∀xA (φψ) ↔ ∀x(xA → (φψ)))
2 ax-2 4 . . . 4 ((xA → (φψ)) → ((xAφ) → (xAψ)))
3219.20ii 692 . . 3 (∀x(xA → (φψ)) → (∀x(xAφ) → ∀x(xAψ)))
41, 3sylbi 174 . 2 (∀xA (φψ) → (∀x(xAφ) → ∀x(xAψ)))
5 df-ral 1205 . 2 (∀xA φ ↔ ∀x(xAφ))
6 df-ral 1205 . 2 (∀xA ψ ↔ ∀x(xAψ))
74, 5, 63imtr4g 426 1 (∀xA (φψ) → (∀xA φ → ∀xA ψ))
Colors of variables: wff set class
Syntax hints:   → wi 2  ∀wal 672   ∈ wcel 1092  ∀wral 1201
This theorem is referenced by:  tfrlem1 2949  tz7.49 2997  abianfp 3000  bnd 3548  kmlem11 3590  osumlem4 5533
This theorem was proved from axioms:  ax-1 3  ax-2 4  ax-3 5  ax-mp 6  ax-4 673  ax-5 674  ax-gen 677
This theorem depends on definitions:  df-bi 128  df-an 198  df-ral 1205
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