Description: Given a, a implies it is not the case a implies a self contradiction. (Contributed by Jarvin Udandy, 7-Sep-2020)
Ref | Expression | ||
---|---|---|---|
Hypothesis | ainaiaandna.1 | |- ph |
|
Assertion | ainaiaandna | |- ( ph -> -. ( ph -> ( ph /\ -. ph ) ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ainaiaandna.1 | |- ph |
|
2 | 1 | atnaiana | |- -. ( ph -> ( ph /\ -. ph ) ) |
3 | 2 | a1i | |- ( ph -> -. ( ph -> ( ph /\ -. ph ) ) ) |