Theorem coeq2 4875

Description: Equality theorem for composition of two classes. (Contributed by set.mm contributors, 3-Jan-1997.)

Assertion

Ref	Expression
coeq2	|- (A = B -> (C o. A) = (C o. B))

Proof of Theorem coeq2

Step	Hyp	Ref	Expression
1		coss2 4873	. . 3 |- (A C_ B -> (C o. A) C_ (C o. B))
2		coss2 4873	. . 3 |- (B C_ A -> (C o. B) C_ (C o. A))
3	1, 2	anim12i 549	. 2 |- ((A C_ B /\ B C_ A) -> ((C o. A) C_ (C o. B) /\ (C o. B) C_ (C o. A)))
4		eqss 3287	. 2 |- (A = B <-> (A C_ B /\ B C_ A))
5		eqss 3287	. 2 |- ((C o. A) = (C o. B) <-> ((C o. A) C_ (C o. B) /\ (C o. B) C_ (C o. A)))
6	3, 4, 5	3imtr4i 257	1 |- (A = B -> (C o. A) = (C o. B))

Syntax hints:   -> wi 4   /\ wa 358   = wceq 1642   C_ wss 3257   o. ccom 4721

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-v 2861  df-nin 3211  df-compl 3212  df-in 3213  df-ss 3259  df-opab 4623  df-br 4640  df-co 4726

This theorem is referenced by:  coeq2i  4877  coeq2d  4879  txpeq1  5779  txpeq2  5780  composevalg  5817  enmap1lem3  6071  enmap1lem5  6073