Description: The converse of a restriction of the converse of a function equals the function restricted to the image of its converse. (Contributed by NM, 4-May-2005)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | funcnvres2 | |- ( Fun F -> `' ( `' F |` A ) = ( F |` ( `' F " A ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | funcnvcnv | |- ( Fun F -> Fun `' `' F ) |
|
| 2 | funcnvres | |- ( Fun `' `' F -> `' ( `' F |` A ) = ( `' `' F |` ( `' F " A ) ) ) |
|
| 3 | 1 2 | syl | |- ( Fun F -> `' ( `' F |` A ) = ( `' `' F |` ( `' F " A ) ) ) |
| 4 | funrel | |- ( Fun F -> Rel F ) |
|
| 5 | dfrel2 | |- ( Rel F <-> `' `' F = F ) |
|
| 6 | 4 5 | sylib | |- ( Fun F -> `' `' F = F ) |
| 7 | 6 | reseq1d | |- ( Fun F -> ( `' `' F |` ( `' F " A ) ) = ( F |` ( `' F " A ) ) ) |
| 8 | 3 7 | eqtrd | |- ( Fun F -> `' ( `' F |` A ) = ( F |` ( `' F " A ) ) ) |