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I was looking at the date today and it made me think of a mathematical object.

Like March 14, which is known by some as as "Pi day".

So the date is 2022-02-02. What mathematical object can it be linked to?

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  • $\begingroup$ Must it be unique like 3/14, or can other similar dates this year hold the same property? $\endgroup$
    – noedne
    Feb 2, 2022 at 18:51
  • $\begingroup$ Other dates have the same property. Not difficult to guess. $\endgroup$
    – Florian F
    Feb 2, 2022 at 19:14

1 Answer 1

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2022-02-02 can be linked to

the Cantor ternary set on the interval $[0,1]$. Informally, this mathematical object is created by repeatedly removing the middle third from each line segment, as seen below.

Cantor ternary set

Credit: 127 "rect" from Wikimedia Commons

It is famous for having certain mathematical properties, such as being a perfect set that is nowhere dense.

This is because

the Cantor set above contains those ternary decimals that can be written without a $1$, and we can associate the date with $0.20220202_3$.

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  • $\begingroup$ Yep! That is what today's date made me think of. $\endgroup$
    – Florian F
    Feb 2, 2022 at 20:10

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