Description: Change bound variable of a class substitution. General version of cbvsbcdavw . Deduction form. (Contributed by GG, 14-Aug-2025)
| Ref | Expression | ||
|---|---|---|---|
| Hypotheses | cbvsbcdavw2.1 | |- ( ph -> A = B ) |
|
| cbvsbcdavw2.2 | |- ( ( ph /\ x = y ) -> ( ps <-> ch ) ) |
||
| Assertion | cbvsbcdavw2 | |- ( ph -> ( [. A / x ]. ps <-> [. B / y ]. ch ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | cbvsbcdavw2.1 | |- ( ph -> A = B ) |
|
| 2 | cbvsbcdavw2.2 | |- ( ( ph /\ x = y ) -> ( ps <-> ch ) ) |
|
| 3 | 2 | cbvabdavw | |- ( ph -> { x | ps } = { y | ch } ) |
| 4 | 1 3 | eleq12d | |- ( ph -> ( A e. { x | ps } <-> B e. { y | ch } ) ) |
| 5 | df-sbc | |- ( [. A / x ]. ps <-> A e. { x | ps } ) |
|
| 6 | df-sbc | |- ( [. B / y ]. ch <-> B e. { y | ch } ) |
|
| 7 | 4 5 6 | 3bitr4g | |- ( ph -> ( [. A / x ]. ps <-> [. B / y ]. ch ) ) |