Metamath Proof Explorer


Theorem nfcriv

Description: Consequence of the not-free predicate, similiar to nfcri . Requires y and A be disjoint, but is not based on ax-13 . (Contributed by Wolf Lammen, 13-May-2023)

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

Proof

Step Hyp Ref Expression
1 nfcriv.1 _ x A
2 nfcr _ x A x y A
3 1 2 ax-mp x y A