Description: An exportation inference. (Contributed by NM, 26-Apr-1994) (Proof shortened by Wolf Lammen, 23-Nov-2012) Shorten exp4a . (Revised by Wolf Lammen, 20-Jul-2021)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | exp4b.1 | |- ( ( ph /\ ps ) -> ( ( ch /\ th ) -> ta ) ) |
|
| Assertion | exp4b | |- ( ph -> ( ps -> ( ch -> ( th -> ta ) ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | exp4b.1 | |- ( ( ph /\ ps ) -> ( ( ch /\ th ) -> ta ) ) |
|
| 2 | 1 | expd | |- ( ( ph /\ ps ) -> ( ch -> ( th -> ta ) ) ) |
| 3 | 2 | ex | |- ( ph -> ( ps -> ( ch -> ( th -> ta ) ) ) ) |