Metamath Proof Explorer


Theorem nfna1

Description: A convenience theorem particularly designed to remove dependencies on ax-11 in conjunction with distinctors. (Contributed by Wolf Lammen, 2-Sep-2018)

Ref Expression
Assertion nfna1
|- F/ x -. A. x ph

Proof

Step Hyp Ref Expression
1 nfa1
 |-  F/ x A. x ph
2 1 nfn
 |-  F/ x -. A. x ph