Description: The identity arrow construction is a function on categories. (Contributed by Mario Carneiro, 17-Jan-2017)
Ref | Expression | ||
---|---|---|---|
Assertion | cidffn | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | vex | |
|
2 | 1 | mptex | |
3 | 2 | csbex | |
4 | 3 | csbex | |
5 | 4 | csbex | |
6 | df-cid | |
|
7 | 5 6 | fnmpti | |