Metamath Proof Explorer


Theorem nfra2w

Description: Similar to Lemma 24 of Monk2 p. 114, except the quantification of the antecedent is restricted. Derived automatically from hbra2VD . Version of nfra2 with a disjoint variable condition, which does not require ax-13 . (Contributed by Alan Sare, 31-Dec-2011) (Revised by Gino Giotto, 10-Jan-2024)

Ref Expression
Assertion nfra2w y x A y B φ

Proof

Step Hyp Ref Expression
1 nfcv _ y A
2 nfra1 y y B φ
3 1 2 nfralw y x A y B φ