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Theorem idfn 6451
 Description: The identity relation is a function on the universal class. See also funi 6360. (Contributed by BJ, 23-Dec-2023.)
Assertion
Ref Expression
idfn I Fn V

Proof of Theorem idfn
StepHypRef Expression
1 funi 6360 . 2 Fun I
2 dmi 5759 . 2 dom I = V
3 df-fn 6331 . 2 ( I Fn V ↔ (Fun I ∧ dom I = V))
41, 2, 3mpbir2an 710 1 I Fn V
 Colors of variables: wff setvar class Syntax hints:   = wceq 1538  Vcvv 3444   I cid 5427  dom cdm 5523  Fun wfun 6322   Fn wfn 6323 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811  ax-5 1911  ax-6 1970  ax-7 2015  ax-8 2114  ax-9 2122  ax-10 2143  ax-11 2159  ax-12 2176  ax-ext 2773  ax-sep 5170  ax-nul 5177  ax-pr 5298 This theorem depends on definitions:  df-bi 210  df-an 400  df-or 845  df-3an 1086  df-tru 1541  df-ex 1782  df-nf 1786  df-sb 2070  df-mo 2601  df-eu 2632  df-clab 2780  df-cleq 2794  df-clel 2873  df-nfc 2941  df-ral 3114  df-rex 3115  df-v 3446  df-dif 3887  df-un 3889  df-in 3891  df-ss 3901  df-nul 4247  df-if 4429  df-sn 4529  df-pr 4531  df-op 4535  df-br 5034  df-opab 5096  df-id 5428  df-xp 5529  df-rel 5530  df-cnv 5531  df-co 5532  df-dm 5533  df-fun 6330  df-fn 6331 This theorem is referenced by:  fnresi  6452
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