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BASIC TOPOLOGY
Topology
Compactness
0cmp
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cmptop
Metamath Proof Explorer
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Theorem
0cmp
Description:
The singleton of the empty set is compact.
(Contributed by
FL
, 2-Aug-2009)
Ref
Expression
Assertion
0cmp
⊢
∅
∈
Comp
Proof
Step
Hyp
Ref
Expression
1
sn0top
⊢
∅
∈
Top
2
snfi
⊢
∅
∈
Fin
3
1
2
elini
⊢
∅
∈
Top
∩
Fin
4
fincmp
⊢
∅
∈
Top
∩
Fin
→
∅
∈
Comp
5
3
4
ax-mp
⊢
∅
∈
Comp