Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - start with the Axiom of Extensionality
Power classes
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Metamath Proof Explorer
Ascii
Unicode
Theorem
pwidg
Description:
A set is an element of its power set.
(Contributed by
Stefan O'Rear
, 1-Feb-2015)
Ref
Expression
Assertion
pwidg
⊢
A
∈
V
→
A
∈
𝒫
A
Proof
Step
Hyp
Ref
Expression
1
ssid
⊢
A
⊆
A
2
elpwg
⊢
A
∈
V
→
A
∈
𝒫
A
↔
A
⊆
A
3
1
2
mpbiri
⊢
A
∈
V
→
A
∈
𝒫
A