Metamath Proof Explorer


Theorem bj-rabtr

Description: Restricted class abstraction with true formula. (Contributed by BJ, 22-Apr-2019)

Ref Expression
Assertion bj-rabtr xA|=A

Proof

Step Hyp Ref Expression
1 ssrab2 xA|A
2 ssid AA
3 tru
4 3 rgenw xA
5 ssrab AxA|AAxA
6 2 4 5 mpbir2an AxA|
7 1 6 eqssi xA|=A