Metamath Proof Explorer


Theorem f1o00

Description: One-to-one onto mapping of the empty set. (Contributed by NM, 15-Apr-1998)

Ref Expression
Assertion f1o00
|- ( F : (/) -1-1-onto-> A <-> ( F = (/) /\ A = (/) ) )

Proof

Step Hyp Ref Expression
1 dff1o4
 |-  ( F : (/) -1-1-onto-> A <-> ( F Fn (/) /\ `' F Fn A ) )
2 fn0
 |-  ( F Fn (/) <-> F = (/) )
3 2 birani
 |-  ( ( F Fn (/) /\ `' F Fn A ) -> F = (/) )
4 cnveq
 |-  ( F = (/) -> `' F = `' (/) )
5 cnv0
 |-  `' (/) = (/)
6 4 5 eqtrdi
 |-  ( F = (/) -> `' F = (/) )
7 2 6 sylbi
 |-  ( F Fn (/) -> `' F = (/) )
8 7 fneq1d
 |-  ( F Fn (/) -> ( `' F Fn A <-> (/) Fn A ) )
9 8 biimpa
 |-  ( ( F Fn (/) /\ `' F Fn A ) -> (/) Fn A )
10 9 fndmd
 |-  ( ( F Fn (/) /\ `' F Fn A ) -> dom (/) = A )
11 dm0
 |-  dom (/) = (/)
12 10 11 eqtr3di
 |-  ( ( F Fn (/) /\ `' F Fn A ) -> A = (/) )
13 3 12 jca
 |-  ( ( F Fn (/) /\ `' F Fn A ) -> ( F = (/) /\ A = (/) ) )
14 2 biranri
 |-  ( ( F = (/) /\ A = (/) ) -> F Fn (/) )
15 eqid
 |-  (/) = (/)
16 fn0
 |-  ( (/) Fn (/) <-> (/) = (/) )
17 15 16 mpbir
 |-  (/) Fn (/)
18 6 fneq1d
 |-  ( F = (/) -> ( `' F Fn A <-> (/) Fn A ) )
19 fneq2
 |-  ( A = (/) -> ( (/) Fn A <-> (/) Fn (/) ) )
20 18 19 sylan9bb
 |-  ( ( F = (/) /\ A = (/) ) -> ( `' F Fn A <-> (/) Fn (/) ) )
21 17 20 mpbiri
 |-  ( ( F = (/) /\ A = (/) ) -> `' F Fn A )
22 14 21 jca
 |-  ( ( F = (/) /\ A = (/) ) -> ( F Fn (/) /\ `' F Fn A ) )
23 13 22 impbii
 |-  ( ( F Fn (/) /\ `' F Fn A ) <-> ( F = (/) /\ A = (/) ) )
24 1 23 bitri
 |-  ( F : (/) -1-1-onto-> A <-> ( F = (/) /\ A = (/) ) )