Thue equation

In mathematics, a Thue equation is a Diophantine equation of the form

where ƒ is an irreducible bivariate form of degree at least 3 over the rational numbers, and r is a nonzero rational number. It is named after Axel Thue who in 1909 proved a theorem, now called Thue's theorem, that a Thue equation has finitely many solutions in integers x and y.

The Thue equation is soluble effectively: there is an explicit bound on the solutions x, y of the form ( C 1 r ) C 2 where constants C₁ and C₂ depend only on the form ƒ. A stronger result holds, that if K is the field generated by the roots of ƒ then the equation has only finitely many solutions with x and y integers of K and again these may be effectively determined.