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SUPPLEMENTARY MATERIAL (USERS' MATHBOXES)
Mathbox for Richard Penner
Short Studies
2finon
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3finon
Metamath Proof Explorer
Ascii
Unicode
Theorem
2finon
Description:
2 is a finite ordinal. See
1onn
.
(Contributed by
RP
, 27-Sep-2023)
Ref
Expression
Assertion
2finon
⊢
2
𝑜
∈
On
∩
Fin
Proof
Step
Hyp
Ref
Expression
1
2onn
ω
⊢
2
𝑜
∈
ω
2
onfin2
ω
⊢
ω
=
On
∩
Fin
3
1
2
eleqtri
⊢
2
𝑜
∈
On
∩
Fin