Metamath Proof Explorer


Theorem exa1

Description: Add an antecedent in an existentially quantified formula. (Contributed by BJ, 6-Oct-2018)

Ref Expression
Assertion exa1
|- ( E. x ph -> E. x ( ps -> ph ) )

Proof

Step Hyp Ref Expression
1 ax-1
 |-  ( ph -> ( ps -> ph ) )
2 1 eximi
 |-  ( E. x ph -> E. x ( ps -> ph ) )