Description: A more efficient proof of Theorem 5.3 of Clemente p. 16. Compare with ex-natded5.3 and ex-natded5.3i . (Contributed by Mario Carneiro, 9-Feb-2017) (Proof modification is discouraged.) (New usage is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | ex-natded5.3.1 | |- ( ph -> ( ps -> ch ) ) |
|
| ex-natded5.3.2 | |- ( ph -> ( ch -> th ) ) |
||
| Assertion | ex-natded5.3-2 | |- ( ph -> ( ps -> ( ch /\ th ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | ex-natded5.3.1 | |- ( ph -> ( ps -> ch ) ) |
|
| 2 | ex-natded5.3.2 | |- ( ph -> ( ch -> th ) ) |
|
| 3 | 1 2 | syld | |- ( ph -> ( ps -> th ) ) |
| 4 | 1 3 | jcad | |- ( ph -> ( ps -> ( ch /\ th ) ) ) |