Description: The image of the double converse of a class. (Contributed by NM, 8-Apr-2007)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | imacnvcnv | |- ( `' `' A " B ) = ( A " B ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | rescnvcnv | |- ( `' `' A |` B ) = ( A |` B ) | |
| 2 | 1 | rneqi | |- ran ( `' `' A |` B ) = ran ( A |` B ) | 
| 3 | df-ima | |- ( `' `' A " B ) = ran ( `' `' A |` B ) | |
| 4 | df-ima | |- ( A " B ) = ran ( A |` B ) | |
| 5 | 2 3 4 | 3eqtr4i | |- ( `' `' A " B ) = ( A " B ) |