Metamath Proof Explorer
Description: If a wff is true, it is true for at least one instance. Deduction form
of 19.8a . (Contributed by DAW, 13-Feb-2017)
|
|
Ref |
Expression |
|
Hypothesis |
19.8ad.1 |
|- ( ph -> ps ) |
|
Assertion |
19.8ad |
|- ( ph -> E. x ps ) |
Proof
| Step |
Hyp |
Ref |
Expression |
| 1 |
|
19.8ad.1 |
|- ( ph -> ps ) |
| 2 |
|
19.8a |
|- ( ps -> E. x ps ) |
| 3 |
1 2
|
syl |
|- ( ph -> E. x ps ) |