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 biimpi
 |-  ( F Fn (/) -> F = (/) )
4 3 adantr
 |-  ( ( F Fn (/) /\ `' F Fn A ) -> F = (/) )
5 cnveq
 |-  ( F = (/) -> `' F = `' (/) )
6 cnv0
 |-  `' (/) = (/)
7 5 6 eqtrdi
 |-  ( F = (/) -> `' F = (/) )
8 2 7 sylbi
 |-  ( F Fn (/) -> `' F = (/) )
9 8 fneq1d
 |-  ( F Fn (/) -> ( `' F Fn A <-> (/) Fn A ) )
10 9 biimpa
 |-  ( ( F Fn (/) /\ `' F Fn A ) -> (/) Fn A )
11 10 fndmd
 |-  ( ( F Fn (/) /\ `' F Fn A ) -> dom (/) = A )
12 dm0
 |-  dom (/) = (/)
13 11 12 eqtr3di
 |-  ( ( F Fn (/) /\ `' F Fn A ) -> A = (/) )
14 4 13 jca
 |-  ( ( F Fn (/) /\ `' F Fn A ) -> ( F = (/) /\ A = (/) ) )
15 2 biimpri
 |-  ( F = (/) -> F Fn (/) )
16 15 adantr
 |-  ( ( F = (/) /\ A = (/) ) -> F Fn (/) )
17 eqid
 |-  (/) = (/)
18 fn0
 |-  ( (/) Fn (/) <-> (/) = (/) )
19 17 18 mpbir
 |-  (/) Fn (/)
20 7 fneq1d
 |-  ( F = (/) -> ( `' F Fn A <-> (/) Fn A ) )
21 fneq2
 |-  ( A = (/) -> ( (/) Fn A <-> (/) Fn (/) ) )
22 20 21 sylan9bb
 |-  ( ( F = (/) /\ A = (/) ) -> ( `' F Fn A <-> (/) Fn (/) ) )
23 19 22 mpbiri
 |-  ( ( F = (/) /\ A = (/) ) -> `' F Fn A )
24 16 23 jca
 |-  ( ( F = (/) /\ A = (/) ) -> ( F Fn (/) /\ `' F Fn A ) )
25 14 24 impbii
 |-  ( ( F Fn (/) /\ `' F Fn A ) <-> ( F = (/) /\ A = (/) ) )
26 1 25 bitri
 |-  ( F : (/) -1-1-onto-> A <-> ( F = (/) /\ A = (/) ) )