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Description: Preimage of an image. (Contributed by NM, 30-Sep-2004)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | f1imacnv | |- ( ( F : A -1-1-> B /\ C C_ A ) -> ( `' F " ( F " C ) ) = C ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | resima | |- ( ( `' F |` ( F " C ) ) " ( F " C ) ) = ( `' F " ( F " C ) ) |
|
| 2 | df-f1 | |- ( F : A -1-1-> B <-> ( F : A --> B /\ Fun `' F ) ) |
|
| 3 | 2 | simprbi | |- ( F : A -1-1-> B -> Fun `' F ) |
| 4 | 3 | adantr | |- ( ( F : A -1-1-> B /\ C C_ A ) -> Fun `' F ) |
| 5 | funcnvres | |- ( Fun `' F -> `' ( F |` C ) = ( `' F |` ( F " C ) ) ) |
|
| 6 | 4 5 | syl | |- ( ( F : A -1-1-> B /\ C C_ A ) -> `' ( F |` C ) = ( `' F |` ( F " C ) ) ) |
| 7 | 6 | imaeq1d | |- ( ( F : A -1-1-> B /\ C C_ A ) -> ( `' ( F |` C ) " ( F " C ) ) = ( ( `' F |` ( F " C ) ) " ( F " C ) ) ) |
| 8 | f1ores | |- ( ( F : A -1-1-> B /\ C C_ A ) -> ( F |` C ) : C -1-1-onto-> ( F " C ) ) |
|
| 9 | f1ocnv | |- ( ( F |` C ) : C -1-1-onto-> ( F " C ) -> `' ( F |` C ) : ( F " C ) -1-1-onto-> C ) |
|
| 10 | 8 9 | syl | |- ( ( F : A -1-1-> B /\ C C_ A ) -> `' ( F |` C ) : ( F " C ) -1-1-onto-> C ) |
| 11 | imadmrn | |- ( `' ( F |` C ) " dom `' ( F |` C ) ) = ran `' ( F |` C ) |
|
| 12 | f1odm | |- ( `' ( F |` C ) : ( F " C ) -1-1-onto-> C -> dom `' ( F |` C ) = ( F " C ) ) |
|
| 13 | 12 | imaeq2d | |- ( `' ( F |` C ) : ( F " C ) -1-1-onto-> C -> ( `' ( F |` C ) " dom `' ( F |` C ) ) = ( `' ( F |` C ) " ( F " C ) ) ) |
| 14 | f1ofo | |- ( `' ( F |` C ) : ( F " C ) -1-1-onto-> C -> `' ( F |` C ) : ( F " C ) -onto-> C ) |
|
| 15 | forn | |- ( `' ( F |` C ) : ( F " C ) -onto-> C -> ran `' ( F |` C ) = C ) |
|
| 16 | 14 15 | syl | |- ( `' ( F |` C ) : ( F " C ) -1-1-onto-> C -> ran `' ( F |` C ) = C ) |
| 17 | 11 13 16 | 3eqtr3a | |- ( `' ( F |` C ) : ( F " C ) -1-1-onto-> C -> ( `' ( F |` C ) " ( F " C ) ) = C ) |
| 18 | 10 17 | syl | |- ( ( F : A -1-1-> B /\ C C_ A ) -> ( `' ( F |` C ) " ( F " C ) ) = C ) |
| 19 | 7 18 | eqtr3d | |- ( ( F : A -1-1-> B /\ C C_ A ) -> ( ( `' F |` ( F " C ) ) " ( F " C ) ) = C ) |
| 20 | 1 19 | eqtr3id | |- ( ( F : A -1-1-> B /\ C C_ A ) -> ( `' F " ( F " C ) ) = C ) |