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Definition df-fun 4018
Description: Define a function. Definition 10.1 of [Quine] p. 65. For alternate definitions, see dffun2 4452, dffun3 4453, dffun4 4454, dffun5 4455, dffun6 4457, dffun7 4467, dffun8 4468, and dffun9 4469.
Assertion
Ref Expression
df-fun |- (Fun A <-> (Rel A /\ (A o. `'A) C_ _I ))

Detailed syntax breakdown of Definition df-fun
StepHypRef Expression
1 cA . . 3 class A
21wfun 4002 . 2 wff Fun A
31wrel 4001 . . 3 wff Rel A
41ccnv 3995 . . . . 5 class `'A
51, 4ccom 4000 . . . 4 class (A o. `'A)
6 cid 3612 . . . 4 class _I
75, 6wss 2642 . . 3 wff (A o. `'A) C_ _I
83, 7wa 361 . 2 wff (Rel A /\ (A o. `'A) C_ _I )
92, 8wb 174 1 wff (Fun A <-> (Rel A /\ (A o. `'A) C_ _I ))
Colors of variables: wff set class
This definition is referenced by:  dffun2 4452  funrel 4459  funss 4460  hbfun 4464  funi 4471  f1ococnv2 4658  dffv2 4735  flimfnei2 16266  cnvcan 17171
Copyright terms: Public domain