Description: Obsolete version of 2falsed as of 11-Apr-2024. (Contributed by NM, 11-Oct-2013) (Proof modification is discouraged.) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | 2falsed.1 | |- ( ph -> -. ps ) |
|
| 2falsed.2 | |- ( ph -> -. ch ) |
||
| Assertion | 2falsedOLD | |- ( ph -> ( ps <-> ch ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | 2falsed.1 | |- ( ph -> -. ps ) |
|
| 2 | 2falsed.2 | |- ( ph -> -. ch ) |
|
| 3 | 1 | pm2.21d | |- ( ph -> ( ps -> ch ) ) |
| 4 | 2 | pm2.21d | |- ( ph -> ( ch -> ps ) ) |
| 5 | 3 4 | impbid | |- ( ph -> ( ps <-> ch ) ) |