Description: Change bound variables in a description binder. Usage of this theorem is discouraged because it depends on ax-13 . Use the weaker cbviotavw when possible. (Contributed by Andrew Salmon, 1-Aug-2011) (New usage is discouraged.)
Ref | Expression | ||
---|---|---|---|
Hypothesis | cbviotav.1 | |- ( x = y -> ( ph <-> ps ) ) |
|
Assertion | cbviotav | |- ( iota x ph ) = ( iota y ps ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | cbviotav.1 | |- ( x = y -> ( ph <-> ps ) ) |
|
2 | nfv | |- F/ y ph |
|
3 | nfv | |- F/ x ps |
|
4 | 1 2 3 | cbviota | |- ( iota x ph ) = ( iota y ps ) |