Metamath Proof Explorer


Theorem ssrab2f

Description: Subclass relation for a restricted class. (Contributed by Glauco Siliprandi, 26-Jun-2021)

Ref Expression
Hypothesis ssrab2f.1 _xA
Assertion ssrab2f xA|φA

Proof

Step Hyp Ref Expression
1 ssrab2f.1 _xA
2 nfrab1 _xxA|φ
3 2 1 dfss3f xA|φAxxA|φxA
4 rabidim1 xxA|φxA
5 3 4 mprgbir xA|φA