Metamath Proof Explorer


Theorem wl-rgen

Description: Generalization rule for restricted quantification. (Contributed by Wolf Lammen, 10-Jun-2023)

Ref Expression
Hypothesis wl-rgen.1 x A φ
Assertion wl-rgen x : A φ

Proof

Step Hyp Ref Expression
1 wl-rgen.1 x A φ
2 wl-dfralv x : A φ x x A φ
3 2 1 mpgbir x : A φ