Description: The empty category (see 0cat ) is thin. (Contributed by Zhi Wang, 17-Sep-2024)
Ref | Expression | ||
---|---|---|---|
Assertion | 0thinc | |- (/) e. ThinCat |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 0ex | |- (/) e. _V |
|
2 | base0 | |- (/) = ( Base ` (/) ) |
|
3 | 0thincg | |- ( ( (/) e. _V /\ (/) = ( Base ` (/) ) ) -> (/) e. ThinCat ) |
|
4 | 1 2 3 | mp2an | |- (/) e. ThinCat |