Database
BASIC TOPOLOGY
Topology
Limit points and perfect sets
perftop
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Subspace topologies
Metamath Proof Explorer
Ascii
Unicode
Theorem
perftop
Description:
A perfect space is a topology.
(Contributed by
Mario Carneiro
, 25-Dec-2016)
Ref
Expression
Assertion
perftop
⊢
J
∈
Perf
→
J
∈
Top
Proof
Step
Hyp
Ref
Expression
1
eqid
⊢
⋃
J
=
⋃
J
2
1
isperf
⊢
J
∈
Perf
↔
J
∈
Top
∧
limPt
⁡
J
⁡
⋃
J
=
⋃
J
3
2
simplbi
⊢
J
∈
Perf
→
J
∈
Top