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Theorem iunin1 4031
 Description: Indexed union of intersection. Generalization of half of theorem "Distributive laws" in [Enderton] p. 30. Use uniiun 4019 to recover Enderton's theorem. (Contributed by Mario Carneiro, 30-Aug-2015.)
Assertion
Ref Expression
iunin1 x A (CB) = (x A CB)
Distinct variable group:   x,B
Allowed substitution hints:   A(x)   C(x)

Proof of Theorem iunin1
StepHypRef Expression
1 iunin2 4030 . 2 x A (BC) = (Bx A C)
2 incom 3448 . . . 4 (CB) = (BC)
32a1i 10 . . 3 (x A → (CB) = (BC))
43iuneq2i 3987 . 2 x A (CB) = x A (BC)
5 incom 3448 . 2 (x A CB) = (Bx A C)
61, 4, 53eqtr4i 2383 1 x A (CB) = (x A CB)
 Colors of variables: wff setvar class Syntax hints:   = wceq 1642   ∈ wcel 1710   ∩ cin 3208  ∪ciun 3969 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-ral 2619  df-rex 2620  df-v 2861  df-nin 3211  df-compl 3212  df-in 3213  df-ss 3259  df-iun 3971 This theorem is referenced by:  2iunin  4034
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