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Theorem unssd 3247
Description: A deduction showing the union of two subclasses is a subclass. (Contributed by Jonathan Ben-Naim, 3-Jun-2011.)
Hypotheses
Ref Expression
unssd.1 (𝜑𝐴𝐶)
unssd.2 (𝜑𝐵𝐶)
Assertion
Ref Expression
unssd (𝜑 → (𝐴𝐵) ⊆ 𝐶)

Proof of Theorem unssd
StepHypRef Expression
1 unssd.1 . 2 (𝜑𝐴𝐶)
2 unssd.2 . 2 (𝜑𝐵𝐶)
3 unss 3245 . . 3 ((𝐴𝐶𝐵𝐶) ↔ (𝐴𝐵) ⊆ 𝐶)
43biimpi 119 . 2 ((𝐴𝐶𝐵𝐶) → (𝐴𝐵) ⊆ 𝐶)
51, 2, 4syl2anc 408 1 (𝜑 → (𝐴𝐵) ⊆ 𝐶)
Colors of variables: wff set class
Syntax hints:  wi 4  wa 103  cun 3064  wss 3066
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 105  ax-ia2 106  ax-ia3 107  ax-io 698  ax-5 1423  ax-7 1424  ax-gen 1425  ax-ie1 1469  ax-ie2 1470  ax-8 1482  ax-10 1483  ax-11 1484  ax-i12 1485  ax-bndl 1486  ax-4 1487  ax-17 1506  ax-i9 1510  ax-ial 1514  ax-i5r 1515  ax-ext 2119
This theorem depends on definitions:  df-bi 116  df-tru 1334  df-nf 1437  df-sb 1736  df-clab 2124  df-cleq 2130  df-clel 2133  df-nfc 2268  df-v 2683  df-un 3070  df-in 3072  df-ss 3079
This theorem is referenced by:  tpssi  3681  casef  6966  un0addcl  9003  un0mulcl  9004  fzosplit  9947  fzouzsplit  9949  exmidunben  11928  strleund  12036  fsumcncntop  12714  bj-omtrans  13143
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