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Theorem unundi 3424
 Description: Union distributes over itself. (Contributed by NM, 17-Aug-2004.)
Assertion
Ref Expression
unundi (A ∪ (BC)) = ((AB) ∪ (AC))

Proof of Theorem unundi
StepHypRef Expression
1 unidm 3407 . . 3 (AA) = A
21uneq1i 3414 . 2 ((AA) ∪ (BC)) = (A ∪ (BC))
3 un4 3423 . 2 ((AA) ∪ (BC)) = ((AB) ∪ (AC))
42, 3eqtr3i 2375 1 (A ∪ (BC)) = ((AB) ∪ (AC))
 Colors of variables: wff setvar class Syntax hints:   = wceq 1642   ∪ cun 3207 This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925  ax-ext 2334 This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-nan 1288  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-clab 2340  df-cleq 2346  df-clel 2349  df-nfc 2478  df-v 2861  df-nin 3211  df-compl 3212  df-un 3214 This theorem is referenced by:  dfif5  3674
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