| Step |
Hyp |
Ref |
Expression |
| 1 |
|
dfifp2 |
|- ( if- ( ph , ( ps <-> ch ) , ( th <-> ta ) ) <-> ( ( ph -> ( ps <-> ch ) ) /\ ( -. ph -> ( th <-> ta ) ) ) ) |
| 2 |
|
dfbi2 |
|- ( ( ps <-> ch ) <-> ( ( ps -> ch ) /\ ( ch -> ps ) ) ) |
| 3 |
2
|
imbi2i |
|- ( ( ph -> ( ps <-> ch ) ) <-> ( ph -> ( ( ps -> ch ) /\ ( ch -> ps ) ) ) ) |
| 4 |
|
jcab |
|- ( ( ph -> ( ( ps -> ch ) /\ ( ch -> ps ) ) ) <-> ( ( ph -> ( ps -> ch ) ) /\ ( ph -> ( ch -> ps ) ) ) ) |
| 5 |
3 4
|
bitri |
|- ( ( ph -> ( ps <-> ch ) ) <-> ( ( ph -> ( ps -> ch ) ) /\ ( ph -> ( ch -> ps ) ) ) ) |
| 6 |
|
dfbi2 |
|- ( ( th <-> ta ) <-> ( ( th -> ta ) /\ ( ta -> th ) ) ) |
| 7 |
6
|
imbi2i |
|- ( ( -. ph -> ( th <-> ta ) ) <-> ( -. ph -> ( ( th -> ta ) /\ ( ta -> th ) ) ) ) |
| 8 |
|
jcab |
|- ( ( -. ph -> ( ( th -> ta ) /\ ( ta -> th ) ) ) <-> ( ( -. ph -> ( th -> ta ) ) /\ ( -. ph -> ( ta -> th ) ) ) ) |
| 9 |
7 8
|
bitri |
|- ( ( -. ph -> ( th <-> ta ) ) <-> ( ( -. ph -> ( th -> ta ) ) /\ ( -. ph -> ( ta -> th ) ) ) ) |
| 10 |
5 9
|
anbi12i |
|- ( ( ( ph -> ( ps <-> ch ) ) /\ ( -. ph -> ( th <-> ta ) ) ) <-> ( ( ( ph -> ( ps -> ch ) ) /\ ( ph -> ( ch -> ps ) ) ) /\ ( ( -. ph -> ( th -> ta ) ) /\ ( -. ph -> ( ta -> th ) ) ) ) ) |
| 11 |
|
an4 |
|- ( ( ( ( ph -> ( ps -> ch ) ) /\ ( ph -> ( ch -> ps ) ) ) /\ ( ( -. ph -> ( th -> ta ) ) /\ ( -. ph -> ( ta -> th ) ) ) ) <-> ( ( ( ph -> ( ps -> ch ) ) /\ ( -. ph -> ( th -> ta ) ) ) /\ ( ( ph -> ( ch -> ps ) ) /\ ( -. ph -> ( ta -> th ) ) ) ) ) |
| 12 |
10 11
|
bitri |
|- ( ( ( ph -> ( ps <-> ch ) ) /\ ( -. ph -> ( th <-> ta ) ) ) <-> ( ( ( ph -> ( ps -> ch ) ) /\ ( -. ph -> ( th -> ta ) ) ) /\ ( ( ph -> ( ch -> ps ) ) /\ ( -. ph -> ( ta -> th ) ) ) ) ) |
| 13 |
|
dfifp2 |
|- ( if- ( ph , ( ps -> ch ) , ( th -> ta ) ) <-> ( ( ph -> ( ps -> ch ) ) /\ ( -. ph -> ( th -> ta ) ) ) ) |
| 14 |
|
ifpimimb |
|- ( if- ( ph , ( ps -> ch ) , ( th -> ta ) ) <-> ( if- ( ph , ps , th ) -> if- ( ph , ch , ta ) ) ) |
| 15 |
13 14
|
bitr3i |
|- ( ( ( ph -> ( ps -> ch ) ) /\ ( -. ph -> ( th -> ta ) ) ) <-> ( if- ( ph , ps , th ) -> if- ( ph , ch , ta ) ) ) |
| 16 |
|
dfifp2 |
|- ( if- ( ph , ( ch -> ps ) , ( ta -> th ) ) <-> ( ( ph -> ( ch -> ps ) ) /\ ( -. ph -> ( ta -> th ) ) ) ) |
| 17 |
|
ifpimimb |
|- ( if- ( ph , ( ch -> ps ) , ( ta -> th ) ) <-> ( if- ( ph , ch , ta ) -> if- ( ph , ps , th ) ) ) |
| 18 |
16 17
|
bitr3i |
|- ( ( ( ph -> ( ch -> ps ) ) /\ ( -. ph -> ( ta -> th ) ) ) <-> ( if- ( ph , ch , ta ) -> if- ( ph , ps , th ) ) ) |
| 19 |
15 18
|
anbi12i |
|- ( ( ( ( ph -> ( ps -> ch ) ) /\ ( -. ph -> ( th -> ta ) ) ) /\ ( ( ph -> ( ch -> ps ) ) /\ ( -. ph -> ( ta -> th ) ) ) ) <-> ( ( if- ( ph , ps , th ) -> if- ( ph , ch , ta ) ) /\ ( if- ( ph , ch , ta ) -> if- ( ph , ps , th ) ) ) ) |
| 20 |
|
dfbi2 |
|- ( ( if- ( ph , ps , th ) <-> if- ( ph , ch , ta ) ) <-> ( ( if- ( ph , ps , th ) -> if- ( ph , ch , ta ) ) /\ ( if- ( ph , ch , ta ) -> if- ( ph , ps , th ) ) ) ) |
| 21 |
19 20
|
bitr4i |
|- ( ( ( ( ph -> ( ps -> ch ) ) /\ ( -. ph -> ( th -> ta ) ) ) /\ ( ( ph -> ( ch -> ps ) ) /\ ( -. ph -> ( ta -> th ) ) ) ) <-> ( if- ( ph , ps , th ) <-> if- ( ph , ch , ta ) ) ) |
| 22 |
1 12 21
|
3bitri |
|- ( if- ( ph , ( ps <-> ch ) , ( th <-> ta ) ) <-> ( if- ( ph , ps , th ) <-> if- ( ph , ch , ta ) ) ) |