Metamath Proof Explorer


Theorem 19.8v

Description: Version of 19.8a with a disjoint variable condition, requiring fewer axioms. Converse of ax5e . (Contributed by BJ, 12-Mar-2020)

Ref Expression
Assertion 19.8v φ x φ

Proof

Step Hyp Ref Expression
1 ax-5 φ x φ
2 1 19.8w φ x φ