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?

  • $\begingroup$ 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


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 $0.20220202_3$.

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

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.