Theorem fv2 5866

Description: Alternate definition of function value. Definition 10.11 of [Quine] p. 68. (Contributed by NM, 30-Apr-2004.) (Proof shortened by Andrew Salmon, 17-Sep-2011.) (Revised by Mario Carneiro, 31-Aug-2015.)

Assertion

Ref	Expression
fv2

Distinct variable groups:   ,,   ,,

Proof of Theorem fv2

Step	Hyp	Ref	Expression
1		df-fv 5601	. 2
2		dfiota2 5557	. 2
3	1, 2	eqtri 2486	1

Syntax hints:  <->wb 184  A.wal 1393  =wceq 1395  {cab 2442  U.cuni 4249   class class class wbr 4452  iotacio 5554  `cfv 5593

This theorem is referenced by:  elfv  5869

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1618  ax-4 1631  ax-5 1704  ax-6 1747  ax-7 1790  ax-10 1837  ax-11 1842  ax-12 1854  ax-13 1999  ax-ext 2435

This theorem depends on definitions:  df-bi 185  df-an 371  df-tru 1398  df-ex 1613  df-nf 1617  df-sb 1740  df-clab 2443  df-cleq 2449  df-clel 2452  df-nfc 2607  df-rex 2813  df-sn 4030  df-uni 4250  df-iota 5556  df-fv 5601