Metamath Proof Explorer
Description: The category ( SetCat1o ) , i.e., thetrivial category, is
terminal. (Contributed by Zhi Wang, 18-Oct-2025)
|
|
Ref |
Expression |
|
Assertion |
setc1oterm |
⊢ ( SetCat ‘ 1o ) ∈ TermCat |
Proof
| Step |
Hyp |
Ref |
Expression |
| 1 |
|
df1o2 |
⊢ 1o = { ∅ } |
| 2 |
|
vsn |
⊢ { V } = ∅ |
| 3 |
2
|
sneqi |
⊢ { { V } } = { ∅ } |
| 4 |
1 3
|
eqtr4i |
⊢ 1o = { { V } } |
| 5 |
4
|
fveq2i |
⊢ ( SetCat ‘ 1o ) = ( SetCat ‘ { { V } } ) |
| 6 |
|
setcsnterm |
⊢ ( SetCat ‘ { { V } } ) ∈ TermCat |
| 7 |
5 6
|
eqeltri |
⊢ ( SetCat ‘ 1o ) ∈ TermCat |