Database
SUPPLEMENTARY MATERIAL (USERS' MATHBOXES)
Mathbox for Zhi Wang
Examples of categories
Thin categories
0thinc
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indthinc
Metamath Proof Explorer
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Theorem
0thinc
Description:
The empty category (see
0cat
) is thin.
(Contributed by
Zhi Wang
, 17-Sep-2024)
Ref
Expression
Assertion
0thinc
⊢
∅
∈
ThinCat
Proof
Step
Hyp
Ref
Expression
1
0ex
⊢
∅
∈
V
2
base0
⊢
∅
=
Base
∅
3
0thincg
⊢
∅
∈
V
∧
∅
=
Base
∅
→
∅
∈
ThinCat
4
1
2
3
mp2an
⊢
∅
∈
ThinCat