Hilbert’s Tenth Problem over the rational numbers
Determine whether Hilbert’s Tenth Problem over the field of rational numbers Q is decidable; specifically, establish whether there exists an algorithm that, given any multivariate polynomial with integer coefficients, decides whether the equation has a solution in the rational numbers.
References
However, the problem remains open when generalized to the field of rational numbers, or contrarily, when restricted to Diophantine equations with bounded complexity, characterized by the number of variables $\nu$ and the degree $\delta$.
— A Formal Proof of Complexity Bounds on Diophantine Equations
(2505.16963 - Bayer et al., 22 May 2025) in Abstract