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Theorem iuneq1 3773
Description: Equality theorem for indexed union. (Contributed by NM, 27-Jun-1998.)
Assertion
Ref Expression
iuneq1 (𝐴 = 𝐵 𝑥𝐴 𝐶 = 𝑥𝐵 𝐶)
Distinct variable groups:   𝑥,𝐴   𝑥,𝐵
Allowed substitution hint:   𝐶(𝑥)

Proof of Theorem iuneq1
StepHypRef Expression
1 iunss1 3771 . . 3 (𝐴𝐵 𝑥𝐴 𝐶 𝑥𝐵 𝐶)
2 iunss1 3771 . . 3 (𝐵𝐴 𝑥𝐵 𝐶 𝑥𝐴 𝐶)
31, 2anim12i 334 . 2 ((𝐴𝐵𝐵𝐴) → ( 𝑥𝐴 𝐶 𝑥𝐵 𝐶 𝑥𝐵 𝐶 𝑥𝐴 𝐶))
4 eqss 3062 . 2 (𝐴 = 𝐵 ↔ (𝐴𝐵𝐵𝐴))
5 eqss 3062 . 2 ( 𝑥𝐴 𝐶 = 𝑥𝐵 𝐶 ↔ ( 𝑥𝐴 𝐶 𝑥𝐵 𝐶 𝑥𝐵 𝐶 𝑥𝐴 𝐶))
63, 4, 53imtr4i 200 1 (𝐴 = 𝐵 𝑥𝐴 𝐶 = 𝑥𝐵 𝐶)
Colors of variables: wff set class
Syntax hints:  wi 4  wa 103   = wceq 1299  wss 3021   ciun 3760
This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-mp 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 671  ax-5 1391  ax-7 1392  ax-gen 1393  ax-ie1 1437  ax-ie2 1438  ax-8 1450  ax-10 1451  ax-11 1452  ax-i12 1453  ax-bndl 1454  ax-4 1455  ax-17 1474  ax-i9 1478  ax-ial 1482  ax-i5r 1483  ax-ext 2082
This theorem depends on definitions:  df-bi 116  df-tru 1302  df-nf 1405  df-sb 1704  df-clab 2087  df-cleq 2093  df-clel 2096  df-nfc 2229  df-ral 2380  df-rex 2381  df-v 2643  df-in 3027  df-ss 3034  df-iun 3762
This theorem is referenced by:  iuneq1d  3783  iununir  3842  iunsuc  4280  rdgisuc1  6211  rdg0  6214  oasuc  6290  omsuc  6298  iunfidisj  6762  fsum2d  11043  fsumiun  11085  iuncld  12066
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