Metamath Proof Explorer


Theorem r19.27v

Description: Restricted quantitifer version of one direction of 19.27 . (Assuming F/_ x A , the other direction holds when A is nonempty, see r19.27zv .) (Contributed by NM, 3-Jun-2004) (Proof shortened by Andrew Salmon, 30-May-2011) (Proof shortened by Wolf Lammen, 17-Jun-2023)

Ref Expression
Assertion r19.27v xAφψxAφψ

Proof

Step Hyp Ref Expression
1 id ψψ
2 1 ralrimivw ψxAψ
3 2 anim2i xAφψxAφxAψ
4 r19.26 xAφψxAφxAψ
5 3 4 sylibr xAφψxAφψ