Step |
Hyp |
Ref |
Expression |
1 |
|
nabctnabc.1 |
|- -. ( ph -> ( ps /\ ch ) ) |
2 |
|
pm4.61 |
|- ( -. ( ph -> ( ps /\ ch ) ) <-> ( ph /\ -. ( ps /\ ch ) ) ) |
3 |
2
|
biimpi |
|- ( -. ( ph -> ( ps /\ ch ) ) -> ( ph /\ -. ( ps /\ ch ) ) ) |
4 |
1 3
|
ax-mp |
|- ( ph /\ -. ( ps /\ ch ) ) |
5 |
4
|
simpli |
|- ph |
6 |
4
|
simpri |
|- -. ( ps /\ ch ) |
7 |
5 6
|
2th |
|- ( ph <-> -. ( ps /\ ch ) ) |
8 |
|
bicom |
|- ( ( ph <-> -. ( ps /\ ch ) ) <-> ( -. ( ps /\ ch ) <-> ph ) ) |
9 |
8
|
biimpi |
|- ( ( ph <-> -. ( ps /\ ch ) ) -> ( -. ( ps /\ ch ) <-> ph ) ) |
10 |
7 9
|
ax-mp |
|- ( -. ( ps /\ ch ) <-> ph ) |
11 |
10
|
biimpi |
|- ( -. ( ps /\ ch ) -> ph ) |
12 |
11
|
con3i |
|- ( -. ph -> -. -. ( ps /\ ch ) ) |
13 |
12
|
notnotrd |
|- ( -. ph -> ( ps /\ ch ) ) |