Metamath Proof Explorer


Theorem nfcrii

Description: Consequence of the not-free predicate. (Contributed by Mario Carneiro, 11-Aug-2016) Avoid ax-10 , ax-11 . (Revised by Gino Giotto, 23-May-2024)

Ref Expression
Hypothesis nfcrii.1 _ x A
Assertion nfcrii y A x y A

Proof

Step Hyp Ref Expression
1 nfcrii.1 _ x A
2 1 nfcri x y A
3 2 nf5ri y A x y A