Step |
Hyp |
Ref |
Expression |
1 |
|
s2f1.i |
|- ( ph -> I e. D ) |
2 |
|
s2f1.j |
|- ( ph -> J e. D ) |
3 |
|
s2f1.1 |
|- ( ph -> I =/= J ) |
4 |
|
0nn0 |
|- 0 e. NN0 |
5 |
4
|
a1i |
|- ( ph -> 0 e. NN0 ) |
6 |
|
1nn0 |
|- 1 e. NN0 |
7 |
6
|
a1i |
|- ( ph -> 1 e. NN0 ) |
8 |
|
0ne1 |
|- 0 =/= 1 |
9 |
8
|
a1i |
|- ( ph -> 0 =/= 1 ) |
10 |
|
f1oprg |
|- ( ( ( 0 e. NN0 /\ I e. D ) /\ ( 1 e. NN0 /\ J e. D ) ) -> ( ( 0 =/= 1 /\ I =/= J ) -> { <. 0 , I >. , <. 1 , J >. } : { 0 , 1 } -1-1-onto-> { I , J } ) ) |
11 |
10
|
3impia |
|- ( ( ( 0 e. NN0 /\ I e. D ) /\ ( 1 e. NN0 /\ J e. D ) /\ ( 0 =/= 1 /\ I =/= J ) ) -> { <. 0 , I >. , <. 1 , J >. } : { 0 , 1 } -1-1-onto-> { I , J } ) |
12 |
5 1 7 2 9 3 11
|
syl222anc |
|- ( ph -> { <. 0 , I >. , <. 1 , J >. } : { 0 , 1 } -1-1-onto-> { I , J } ) |
13 |
|
s2prop |
|- ( ( I e. D /\ J e. D ) -> <" I J "> = { <. 0 , I >. , <. 1 , J >. } ) |
14 |
1 2 13
|
syl2anc |
|- ( ph -> <" I J "> = { <. 0 , I >. , <. 1 , J >. } ) |
15 |
14
|
f1oeq1d |
|- ( ph -> ( <" I J "> : { 0 , 1 } -1-1-onto-> { I , J } <-> { <. 0 , I >. , <. 1 , J >. } : { 0 , 1 } -1-1-onto-> { I , J } ) ) |
16 |
12 15
|
mpbird |
|- ( ph -> <" I J "> : { 0 , 1 } -1-1-onto-> { I , J } ) |
17 |
|
f1of1 |
|- ( <" I J "> : { 0 , 1 } -1-1-onto-> { I , J } -> <" I J "> : { 0 , 1 } -1-1-> { I , J } ) |
18 |
16 17
|
syl |
|- ( ph -> <" I J "> : { 0 , 1 } -1-1-> { I , J } ) |
19 |
1 2
|
prssd |
|- ( ph -> { I , J } C_ D ) |
20 |
|
f1ss |
|- ( ( <" I J "> : { 0 , 1 } -1-1-> { I , J } /\ { I , J } C_ D ) -> <" I J "> : { 0 , 1 } -1-1-> D ) |
21 |
18 19 20
|
syl2anc |
|- ( ph -> <" I J "> : { 0 , 1 } -1-1-> D ) |
22 |
|
f1dm |
|- ( <" I J "> : { 0 , 1 } -1-1-> D -> dom <" I J "> = { 0 , 1 } ) |
23 |
21 22
|
syl |
|- ( ph -> dom <" I J "> = { 0 , 1 } ) |
24 |
|
f1eq2 |
|- ( dom <" I J "> = { 0 , 1 } -> ( <" I J "> : dom <" I J "> -1-1-> D <-> <" I J "> : { 0 , 1 } -1-1-> D ) ) |
25 |
23 24
|
syl |
|- ( ph -> ( <" I J "> : dom <" I J "> -1-1-> D <-> <" I J "> : { 0 , 1 } -1-1-> D ) ) |
26 |
21 25
|
mpbird |
|- ( ph -> <" I J "> : dom <" I J "> -1-1-> D ) |