Theorem funeq 5397

Description: Equality theorem for function predicate. (Contributed by NM, 16-Aug-1994.)

Assertion

Ref	Expression
funeq	|- ( A = B -> ( Fun A <-> Fun B ) )

Proof of Theorem funeq

Step	Hyp	Ref	Expression
1		eqimss2 3303	. . 3 |- ( A = B -> B C_ A )
2		funss 5396	. . 3 |- ( B C_ A -> ( Fun A -> Fun B ) )
3	1, 2	syl 14	. 2 |- ( A = B -> ( Fun A -> Fun B ) )
4		eqimss 3302	. . 3 |- ( A = B -> A C_ B )
5		funss 5396	. . 3 |- ( A C_ B -> ( Fun B -> Fun A ) )
6	4, 5	syl 14	. 2 |- ( A = B -> ( Fun B -> Fun A ) )
7	3, 6	impbid 129	1 |- ( A = B -> ( Fun A <-> Fun B ) )

This proof depends on syntax axioms:   -> wi 4   <-> wb 105   = wceq 1402   C_ wss 3220   Fun wfun 5371

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-io 721  ax-5 1500  ax-7 1501  ax-gen 1502  ax-ie1 1546  ax-ie2 1547  ax-8 1557  ax-10 1558  ax-11 1559  ax-i12 1560  ax-bndl 1562  ax-4 1563  ax-17 1579  ax-i9 1583  ax-ial 1587  ax-i5r 1588  ax-ext 2220

This proof depends on definitions:  df-bi 117  df-nf 1514  df-sb 1816  df-clab 2225  df-cleq 2231  df-clel 2234  df-nfc 2381  df-in 3226  df-ss 3233  df-br 4131  df-opab 4193  df-rel 4781  df-cnv 4782  df-co 4783  df-fun 5379

This theorem is used by:  funeqi  5398  funeqd  5399  fununi  5449  funcnvuni  5450  cnvresid  5455  fneq1  5469  funop  5892  elpmg  6938  fundmeng  7095  isfsupp  7289  usgredgop  16414