Step |
Hyp |
Ref |
Expression |
1 |
|
fpr.1 |
|- A e. _V |
2 |
|
fpr.2 |
|- B e. _V |
3 |
|
fpr.3 |
|- C e. _V |
4 |
|
fpr.4 |
|- D e. _V |
5 |
1 2 3 4
|
funpr |
|- ( A =/= B -> Fun { <. A , C >. , <. B , D >. } ) |
6 |
3 4
|
dmprop |
|- dom { <. A , C >. , <. B , D >. } = { A , B } |
7 |
|
df-fn |
|- ( { <. A , C >. , <. B , D >. } Fn { A , B } <-> ( Fun { <. A , C >. , <. B , D >. } /\ dom { <. A , C >. , <. B , D >. } = { A , B } ) ) |
8 |
5 6 7
|
sylanblrc |
|- ( A =/= B -> { <. A , C >. , <. B , D >. } Fn { A , B } ) |
9 |
|
df-pr |
|- { <. A , C >. , <. B , D >. } = ( { <. A , C >. } u. { <. B , D >. } ) |
10 |
9
|
rneqi |
|- ran { <. A , C >. , <. B , D >. } = ran ( { <. A , C >. } u. { <. B , D >. } ) |
11 |
|
rnun |
|- ran ( { <. A , C >. } u. { <. B , D >. } ) = ( ran { <. A , C >. } u. ran { <. B , D >. } ) |
12 |
1
|
rnsnop |
|- ran { <. A , C >. } = { C } |
13 |
2
|
rnsnop |
|- ran { <. B , D >. } = { D } |
14 |
12 13
|
uneq12i |
|- ( ran { <. A , C >. } u. ran { <. B , D >. } ) = ( { C } u. { D } ) |
15 |
|
df-pr |
|- { C , D } = ( { C } u. { D } ) |
16 |
14 15
|
eqtr4i |
|- ( ran { <. A , C >. } u. ran { <. B , D >. } ) = { C , D } |
17 |
10 11 16
|
3eqtri |
|- ran { <. A , C >. , <. B , D >. } = { C , D } |
18 |
17
|
eqimssi |
|- ran { <. A , C >. , <. B , D >. } C_ { C , D } |
19 |
|
df-f |
|- ( { <. A , C >. , <. B , D >. } : { A , B } --> { C , D } <-> ( { <. A , C >. , <. B , D >. } Fn { A , B } /\ ran { <. A , C >. , <. B , D >. } C_ { C , D } ) ) |
20 |
8 18 19
|
sylanblrc |
|- ( A =/= B -> { <. A , C >. , <. B , D >. } : { A , B } --> { C , D } ) |