Description: The objects of a subcategory are a subset of the objects of the original. (Contributed by Mario Carneiro, 4-Jan-2017)
Ref | Expression | ||
---|---|---|---|
Hypotheses | subcss1.1 | |
|
subcss1.2 | |
||
subcss1.b | |
||
Assertion | subcss1 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | subcss1.1 | |
|
2 | subcss1.2 | |
|
3 | subcss1.b | |
|
4 | eqid | |
|
5 | 4 3 | homffn | |
6 | 5 | a1i | |
7 | 1 4 | subcssc | |
8 | 2 6 7 | ssc1 | |