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Theorem albiim 1891
Description: Split a biconditional and distribute quantifier. (Contributed by NM, 18-Aug-1993.)
Assertion
Ref Expression
albiim (∀𝑥(𝜑𝜓) ↔ (∀𝑥(𝜑𝜓) ∧ ∀𝑥(𝜓𝜑)))

Proof of Theorem albiim
StepHypRef Expression
1 dfbi2 478 . . 3 ((𝜑𝜓) ↔ ((𝜑𝜓) ∧ (𝜓𝜑)))
21albii 1821 . 2 (∀𝑥(𝜑𝜓) ↔ ∀𝑥((𝜑𝜓) ∧ (𝜓𝜑)))
3 19.26 1872 . 2 (∀𝑥((𝜑𝜓) ∧ (𝜓𝜑)) ↔ (∀𝑥(𝜑𝜓) ∧ ∀𝑥(𝜓𝜑)))
42, 3bitri 278 1 (∀𝑥(𝜑𝜓) ↔ (∀𝑥(𝜑𝜓) ∧ ∀𝑥(𝜓𝜑)))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 209  wa 399  wal 1536
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811
This theorem depends on definitions:  df-bi 210  df-an 400
This theorem is referenced by:  2albiim  1892  dfmoeu  2619  mobi  2630  eu6lem  2658  eu1  2694  eqss  3958  ssext  5320  asymref2  5950  rabeqsnd  30249  pm14.122a  40937
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