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Theorem 2nd0 7976
Description: The value of the second-member function at the empty set. (Contributed by NM, 23-Apr-2007.)
Assertion
Ref Expression
2nd0 (2nd ‘∅) = ∅

Proof of Theorem 2nd0
StepHypRef Expression
1 2ndval 7972 . 2 (2nd ‘∅) = ran {∅}
2 dmsn0 6199 . . . 4 dom {∅} = ∅
3 dm0rn0 5915 . . . 4 (dom {∅} = ∅ ↔ ran {∅} = ∅)
42, 3mpbi 229 . . 3 ran {∅} = ∅
54unieqi 4912 . 2 ran {∅} =
6 uni0 4930 . 2 ∅ = ∅
71, 5, 63eqtri 2756 1 (2nd ‘∅) = ∅
Colors of variables: wff setvar class
Syntax hints:   = wceq 1533  c0 4315  {csn 4621   cuni 4900  dom cdm 5667  ran crn 5668  cfv 6534  2nd c2nd 7968
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1789  ax-4 1803  ax-5 1905  ax-6 1963  ax-7 2003  ax-8 2100  ax-9 2108  ax-10 2129  ax-11 2146  ax-12 2163  ax-ext 2695  ax-sep 5290  ax-nul 5297  ax-pr 5418  ax-un 7719
This theorem depends on definitions:  df-bi 206  df-an 396  df-or 845  df-3an 1086  df-tru 1536  df-fal 1546  df-ex 1774  df-nf 1778  df-sb 2060  df-mo 2526  df-eu 2555  df-clab 2702  df-cleq 2716  df-clel 2802  df-nfc 2877  df-ne 2933  df-ral 3054  df-rex 3063  df-rab 3425  df-v 3468  df-dif 3944  df-un 3946  df-in 3948  df-ss 3958  df-nul 4316  df-if 4522  df-sn 4622  df-pr 4624  df-op 4628  df-uni 4901  df-br 5140  df-opab 5202  df-mpt 5223  df-id 5565  df-xp 5673  df-rel 5674  df-cnv 5675  df-co 5676  df-dm 5677  df-rn 5678  df-iota 6486  df-fun 6536  df-fv 6542  df-2nd 7970
This theorem is referenced by:  smfval  30330
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