Additive Rigidity for xx-Coordinates of Rational Points on Elliptic Curves

This paper establishes that the number of rational points on an elliptic curve whose xx-coordinates lie in a dd-dimensional generalized arithmetic progression is bounded by a constant raised to the power of the curve's Mordell-Weil rank, a result derived by combining gap principles for large canonical heights with spherical code bounds and which implies restrictions on sets of points with small sumsets.

Seokhyun Choi2026-03-06🔢 math

Numerically stable evaluation of closed-form expressions for eigenvalues of 3×33 \times 3 matrices

This paper presents numerically stable, closed-form algorithms for computing the eigenvalues of real, diagonalizable 3×33 \times 3 matrices using four specific invariants, demonstrating that these methods are both more accurate for repeated eigenvalues and approximately ten times faster than the LAPACK library while maintaining comparable precision.

Michal Habera, Andreas Zilian2026-03-06🔢 math