Ivan Shishkin, Pine Forest

Weekly Problem Design Contest

Contest open

The Disappearance

Starts Saturday, September 26, 2026 Deadline Friday, October 2, 2026 · Paris time Prize 100 reputation points

Create a problem based on the theme “The Disappearance”.

Your problem must involve, in one way or another, something that disappears, in the broadest possible sense: an object that is removed, an element that fades away, an unexpected absence, a configuration that becomes simpler, or any other interpretation of the idea of “disappearance”.

How entries are judged

  • Relevance to the theme of the week
  • Originality: your problem must be created specifically for this contest
  • Mathematical interest
  • Clarity
  • Presentation

Rules

One entry per person. You may edit your problem until Friday at 23:00, Paris time. Admins select one winner and may also award honorable mentions. Translations of the same problem count as one entry.

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Entries

1
48La disparition d’un chiffreFRAncient Tree

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