Theorem psseq12d 3364

Description: An equality deduction for the proper subclass relationship. (Contributed by NM, 9-Jun-2004.)

Hypotheses

Ref	Expression
psseq1d.1	|- (ph -> A = B)
psseq12d.2	|- (ph -> C = D)

Assertion

Ref	Expression
psseq12d	|- (ph -> (A C. C <-> B C. D))

Proof of Theorem psseq12d

Step	Hyp	Ref	Expression
1		psseq1d.1	. . 3 |- (ph -> A = B)
2	1	psseq1d 3362	. 2 |- (ph -> (A C. C <-> B C. C))
3		psseq12d.2	. . 3 |- (ph -> C = D)
4	3	psseq2d 3363	. 2 |- (ph -> (B C. C <-> B C. D))
5	2, 4	bitrd 244	1 |- (ph -> (A C. C <-> B C. D))

Syntax hints:   -> wi 4   <-> wb 176   = wceq 1642   C. wpss 3259

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 2479  df-ne 2519  df-v 2862  df-nin 3212  df-compl 3213  df-in 3214  df-ss 3260  df-pss 3262

This theorem is referenced by: (None)