Description: Version of hbsb3 with a disjoint variable condition, which does not require ax-13 . (Remark: the unbundled version of nfs1 is given by bj-nfs1v .) (Contributed by BJ, 11-Sep-2019) (Proof modification is discouraged.)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | bj-hbsb3v.1 | |- ( ph -> A. y ph ) | |
| Assertion | bj-hbsb3v | |- ( [ y / x ] ph -> A. x [ y / x ] ph ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | bj-hbsb3v.1 | |- ( ph -> A. y ph ) | |
| 2 | 1 | sbimi | |- ( [ y / x ] ph -> [ y / x ] A. y ph ) | 
| 3 | bj-hbsb2av | |- ( [ y / x ] A. y ph -> A. x [ y / x ] ph ) | |
| 4 | 2 3 | syl | |- ( [ y / x ] ph -> A. x [ y / x ] ph ) |