Theorem foeq123d 5436

Description: Equality deduction for onto functions. (Contributed by Mario Carneiro, 27-Jan-2017.)

Hypotheses

Ref	Expression
f1eq123d.1	|- ( ph -> F = G )
f1eq123d.2	|- ( ph -> A = B )
f1eq123d.3	|- ( ph -> C = D )

Assertion

Ref	Expression
foeq123d	|- ( ph -> ( F : A -onto-> C <-> G : B -onto-> D ) )

Proof of Theorem foeq123d

Step	Hyp	Ref	Expression
1		f1eq123d.1	. . 3 |- ( ph -> F = G )
2		foeq1 5416	. . 3 |- ( F = G -> ( F : A -onto-> C <-> G : A -onto-> C ) )
3	1, 2	syl 14	. 2 |- ( ph -> ( F : A -onto-> C <-> G : A -onto-> C ) )
4		f1eq123d.2	. . 3 |- ( ph -> A = B )
5		foeq2 5417	. . 3 |- ( A = B -> ( G : A -onto-> C <-> G : B -onto-> C ) )
6	4, 5	syl 14	. 2 |- ( ph -> ( G : A -onto-> C <-> G : B -onto-> C ) )
7		f1eq123d.3	. . 3 |- ( ph -> C = D )
8		foeq3 5418	. . 3 |- ( C = D -> ( G : B -onto-> C <-> G : B -onto-> D ) )
9	7, 8	syl 14	. 2 |- ( ph -> ( G : B -onto-> C <-> G : B -onto-> D ) )
10	3, 6, 9	3bitrd 213	1 |- ( ph -> ( F : A -onto-> C <-> G : B -onto-> D ) )

Syntax hints:   -> wi 4   <-> wb 104   = wceq 1348   -onto->wfo 5196

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 704  ax-5 1440  ax-7 1441  ax-gen 1442  ax-ie1 1486  ax-ie2 1487  ax-8 1497  ax-10 1498  ax-11 1499  ax-i12 1500  ax-bndl 1502  ax-4 1503  ax-17 1519  ax-i9 1523  ax-ial 1527  ax-i5r 1528  ax-ext 2152

This theorem depends on definitions:  df-bi 116  df-3an 975  df-tru 1351  df-nf 1454  df-sb 1756  df-clab 2157  df-cleq 2163  df-clel 2166  df-nfc 2301  df-v 2732  df-un 3125  df-in 3127  df-ss 3134  df-sn 3589  df-pr 3590  df-op 3592  df-br 3990  df-opab 4051  df-rel 4618  df-cnv 4619  df-co 4620  df-dm 4621  df-rn 4622  df-fun 5200  df-fn 5201  df-fo 5204

This theorem is referenced by:  ctssexmid  7126  ctiunctal  12396  unct  12397