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SUPPLEMENTARY MATERIAL (USERS' MATHBOXES)
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Initial, terminal and zero objects of a category
termoo2
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zeroo2
Metamath Proof Explorer
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Theorem
termoo2
Description:
A terminal object is an object in the base set.
(Contributed by
Zhi Wang
, 23-Oct-2025)
Ref
Expression
Hypothesis
initoo2.b
⊢
B
=
Base
C
Assertion
termoo2
⊢
O
∈
TermO
⁡
C
→
O
∈
B
Proof
Step
Hyp
Ref
Expression
1
initoo2.b
⊢
B
=
Base
C
2
eqid
⊢
Hom
⁡
C
=
Hom
⁡
C
3
termorcl
⊢
O
∈
TermO
⁡
C
→
C
∈
Cat
4
1
2
3
istermoi
⊢
O
∈
TermO
⁡
C
∧
O
∈
TermO
⁡
C
→
O
∈
B
∧
∀
b
∈
B
∃!
h
h
∈
b
Hom
⁡
C
O
5
4
anidms
⊢
O
∈
TermO
⁡
C
→
O
∈
B
∧
∀
b
∈
B
∃!
h
h
∈
b
Hom
⁡
C
O
6
5
simpld
⊢
O
∈
TermO
⁡
C
→
O
∈
B