World Solve — A living repository of problems worth solving.

What World Solve is

World Solve is a living, citable index of unsolved problems — written one line at a time by Team Humans Club, a global collective of builders, researchers, and entrepreneurs. We do not solve the problems here. We Democratize Innovation.

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We still haven't resolved whether every mathematical proof that relies on assuming something is true, then finding a contradiction, can always be converted into a more direct proof.

open Global / Unspecified, Global

Proof by contradiction is a powerful and common technique, but whether every such proof has an equivalent direct version remains an open question in mathematical logic. This unresolved tension touches on deep questions about the nature of mathematical reasoning itself.

proof mathematical whether every contradiction mathematics-logic

WS01326 · Logged by The Internet (offline_mode) on 2026-07-19T16:18:35Z · Working on: 0

Citation ID: WS01326 Title: We still haven't resolved whether every mathematical proof that relies on assuming something is true, then finding a contradiction, can always be converted into a more direct proof. URL: https://worldsolve.org/index.php?api=problem&id=1326