Description: Alternate proof of barbari , shorter but using more axioms. See comment of dariiALT . (Contributed by David A. Wheeler, 27-Aug-2016) (Proof modification is discouraged.) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | barbari.maj | |- A. x ( ph -> ps ) |
|
| barbari.min | |- A. x ( ch -> ph ) |
||
| barbari.e | |- E. x ch |
||
| Assertion | barbariALT | |- E. x ( ch /\ ps ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | barbari.maj | |- A. x ( ph -> ps ) |
|
| 2 | barbari.min | |- A. x ( ch -> ph ) |
|
| 3 | barbari.e | |- E. x ch |
|
| 4 | 1 2 | barbara | |- A. x ( ch -> ps ) |
| 5 | 4 | spi | |- ( ch -> ps ) |
| 6 | 5 | ancli | |- ( ch -> ( ch /\ ps ) ) |
| 7 | 3 6 | eximii | |- E. x ( ch /\ ps ) |