Metamath Proof Explorer


Theorem nfaba1g

Description: Bound-variable hypothesis builder for a class abstraction. Usage of this theorem is discouraged because it depends on ax-13 . See nfaba1 for a version with a disjoint variable condition, but not requiring ax-13 . (Contributed by Mario Carneiro, 14-Oct-2016) (New usage is discouraged.)

Ref Expression
Assertion nfaba1g
|- F/_ x { y | A. x ph }

Proof

Step Hyp Ref Expression
1 nfa1
 |-  F/ x A. x ph
2 1 nfabg
 |-  F/_ x { y | A. x ph }