Metamath Proof Explorer


Theorem hbsbwOLD

Description: Obsolete version of hbsbw as of 23-May-2024. (Contributed by NM, 12-Aug-1993) (Revised by Gino Giotto, 10-Jan-2024) (Proof modification is discouraged.) (New usage is discouraged.)

Ref Expression
Hypothesis hbsbwOLD.1
|- ( ph -> A. z ph )
Assertion hbsbwOLD
|- ( [ y / x ] ph -> A. z [ y / x ] ph )

Proof

Step Hyp Ref Expression
1 hbsbwOLD.1
 |-  ( ph -> A. z ph )
2 1 nf5i
 |-  F/ z ph
3 2 nfsbv
 |-  F/ z [ y / x ] ph
4 3 nf5ri
 |-  ( [ y / x ] ph -> A. z [ y / x ] ph )