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Theorem psseq12d 3363
 Description: An equality deduction for the proper subclass relationship. (Contributed by NM, 9-Jun-2004.)
Hypotheses
Ref Expression
psseq1d.1 (φA = B)
psseq12d.2 (φC = D)
Assertion
Ref Expression
psseq12d (φ → (ACBD))

Proof of Theorem psseq12d
StepHypRef Expression
1 psseq1d.1 . . 3 (φA = B)
21psseq1d 3361 . 2 (φ → (ACBC))
3 psseq12d.2 . . 3 (φC = D)
43psseq2d 3362 . 2 (φ → (BCBD))
52, 4bitrd 244 1 (φ → (ACBD))
 Colors of variables: wff setvar class Syntax hints:   → wi 4   ↔ wb 176   = wceq 1642   ⊊ wpss 3258 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 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-ne 2518  df-v 2861  df-nin 3211  df-compl 3212  df-in 3213  df-ss 3259  df-pss 3261 This theorem is referenced by: (None)
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