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Beal's Conjecture

open

Posed by Andrew Beal · 1993 · number theory · ~1 min read · difficulty 4/5

exponential-diophantine

The problem

Claim: if \(A^x + B^y = C^z\) holds in coprime positive integers with \(\min(x,y,z) \geq 3\), then \(A, B, C\) share a common prime factor. (Exponent 2 is genuinely different — Pythagorean triples show why the bound is sharp.) It generalises Fermat and carries a $1M prize.

History & significance

Formulated by Dallas banker Andrew Beal in 1993 while investigating Fermat patterns; he raised the prize to $1,000,000 (administered by the American Mathematical Society) in 2013. It generalises FLT and sits inside the Fermat–Catalan programme: Tijdeman's framework shows fixed exponent triples yield finitely many primitive solutions (several fully dispatched — e.g. x=y=z=3 is FLT itself; (2,3,7)-type equations resolved via modularity and hyperelliptic methods). The uniform statement resists everything thrown at it.

Still open.

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