Description: If a proposition is implied by x e. _V (which is true, see vex ) and another antecedent, then it is implied by that other antecedent. Deduction associated with elv . (Contributed by Peter Mazsa, 23-Oct-2018)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | elvd.1 | |- ( ( ph /\ x e. _V ) -> ps ) |
|
| Assertion | elvd | |- ( ph -> ps ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | elvd.1 | |- ( ( ph /\ x e. _V ) -> ps ) |
|
| 2 | vex | |- x e. _V |
|
| 3 | 2 1 | mpan2 | |- ( ph -> ps ) |