Description: Change bound variables in a description binder. Version of cbviotav with a disjoint variable condition, which does not require ax-13 . (Contributed by Andrew Salmon, 1-Aug-2011) (Revised by Gino Giotto, 26-Jan-2024)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | cbviotavw.1 | |- ( x = y -> ( ph <-> ps ) ) |
|
| Assertion | cbviotavw | |- ( iota x ph ) = ( iota y ps ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | cbviotavw.1 | |- ( x = y -> ( ph <-> ps ) ) |
|
| 2 | nfv | |- F/ y ph |
|
| 3 | nfv | |- F/ x ps |
|
| 4 | 1 2 3 | cbviotaw | |- ( iota x ph ) = ( iota y ps ) |