This is an inofficial mirror of http://metamath.tirix.org for personal testing of a visualizer extension only.
Metamath Proof Explorer
Description: Inference form of 19.21 and also deduction form of sp .
(Contributed by NM, 26-May-1993)
|
|
Ref |
Expression |
|
Hypothesis |
19.21bi.1 |
|- ( ph -> A. x ps ) |
|
Assertion |
19.21bi |
|- ( ph -> ps ) |
Proof
| Step |
Hyp |
Ref |
Expression |
| 1 |
|
19.21bi.1 |
|- ( ph -> A. x ps ) |
| 2 |
|
sp |
|- ( A. x ps -> ps ) |
| 3 |
1 2
|
syl |
|- ( ph -> ps ) |