Metamath Proof Explorer


Theorem bj-nnfad

Description: Nonfreeness implies the equivalent of ax-5 , deduction form. See nf5rd . (Contributed by BJ, 2-Dec-2023)

Ref Expression
Hypothesis bj-nnfad.1 φℲ'xψ
Assertion bj-nnfad φψxψ

Proof

Step Hyp Ref Expression
1 bj-nnfad.1 φℲ'xψ
2 bj-nnfa Ⅎ'xψψxψ
3 1 2 syl φψxψ