Description: An initial object is an object. (Contributed by AV, 14-Apr-2020)
Ref | Expression | ||
---|---|---|---|
Assertion | initoo | |- ( C e. Cat -> ( O e. ( InitO ` C ) -> O e. ( Base ` C ) ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eqid | |- ( Base ` C ) = ( Base ` C ) |
|
2 | eqid | |- ( Hom ` C ) = ( Hom ` C ) |
|
3 | id | |- ( C e. Cat -> C e. Cat ) |
|
4 | 1 2 3 | isinitoi | |- ( ( C e. Cat /\ O e. ( InitO ` C ) ) -> ( O e. ( Base ` C ) /\ A. b e. ( Base ` C ) E! h h e. ( O ( Hom ` C ) b ) ) ) |
5 | 4 | simpld | |- ( ( C e. Cat /\ O e. ( InitO ` C ) ) -> O e. ( Base ` C ) ) |
6 | 5 | ex | |- ( C e. Cat -> ( O e. ( InitO ` C ) -> O e. ( Base ` C ) ) ) |