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Description: A general instance of Theorem *5.11 of WhiteheadRussell p. 123. (Contributed by NM, 3-Jan-2005)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | pm5.11g | |- ( ( ph -> ps ) \/ ( -. ph -> ch ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | pm2.5g | |- ( -. ( ph -> ps ) -> ( -. ph -> ch ) ) |
|
| 2 | 1 | orri | |- ( ( ph -> ps ) \/ ( -. ph -> ch ) ) |