Metamath Proof Explorer


Theorem rsp

Description: Restricted specialization. (Contributed by NM, 17-Oct-1996)

Ref Expression
Assertion rsp xAφxAφ

Proof

Step Hyp Ref Expression
1 df-ral xAφxxAφ
2 sp xxAφxAφ
3 1 2 sylbi xAφxAφ