Theorem feq3 5212

Description: Equality theorem for functions. (Contributed by set.mm contributors, 1-Aug-1994.)

Assertion

Ref	Expression
feq3	⊢ (A = B → (F:C–→A ↔ F:C–→B))

Proof of Theorem feq3

Step	Hyp	Ref	Expression
1		sseq2 3293	. . 3 ⊢ (A = B → (ran F ⊆ A ↔ ran F ⊆ B))
2	1	anbi2d 684	. 2 ⊢ (A = B → ((F Fn C ∧ ran F ⊆ A) ↔ (F Fn C ∧ ran F ⊆ B)))
3		df-f 4791	. 2 ⊢ (F:C–→A ↔ (F Fn C ∧ ran F ⊆ A))
4		df-f 4791	. 2 ⊢ (F:C–→B ↔ (F Fn C ∧ ran F ⊆ B))
5	2, 3, 4	3bitr4g 279	1 ⊢ (A = B → (F:C–→A ↔ F:C–→B))

Syntax hints:   → wi 4   ↔ wb 176   ∧ wa 358   = wceq 1642   ⊆ wss 3257  ran crn 4773   Fn wfn 4776  –→wf 4777

This theorem was proved from axioms:  ax-1 5  ax-2 6  ax-3 7  ax-mp 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-f 4791

This theorem is referenced by:  feq23  5213  fconstg  5251  f1eq3  5255  fsng  5433  fsn2  5434  mapex  6006  mapvalg  6009  mapsn  6026