tl;dr: A user (levent/@__alpoge__) claims that Claude "Fable" produced a counterexample to the Jacobian Conjecture, a longstanding open problem in algebraic geometry. The proposed map from ℂ³ to ℂ³ has constant Jacobian determinant -2 but is not injective, sending three distinct points to (-1/4, 0, 0). If verified, this would disprove the conjecture, which posits that polynomial maps with nonzero constant Jacobian determinant must be invertible.