Sampling Polynomial Rational Remainders with SP$\mathbb{Q}$R: A new Package for Polynomial Division and Elimination
Vsevolod Chestnov, Giulio Crisanti
TL;DR
The paper introduces SP$\mathbb{Q}$R, a Mathematica package that performs polynomial division and variable elimination through finite-field sampling and reconstruction, thereby avoiding intermediate expression swell common in Gröbner-basis methods. By leveraging companion matrices, elimination theory, and a FiniteFlow back end, SP$\mathbb{Q}$R achieves substantial speedups and memory reductions on parameter-rich problems, notably in Macaulay resultants and Landau analysis for Feynman integrals. The authors provide a detailed theoretical and implementation framework, practical installation and usage guidance, and demonstrations showing new Landau singularities and competitive performance against state-of-the-art CAS. The work highlights when this finite-field, linear-algebra–centric approach is advantageous and outlines future improvements, including tighter integration with numerical Gröbner-basis procedures and enhanced reconstruction techniques. SP$\mathbb{Q}$R thus offers a scalable, parametric-aware toolkit for polynomial algebra with broad applicability in mathematics and high-energy physics.
Abstract
We introduce SP$\mathbb{Q}$R, a new Mathematica package for the division and elimination of variables from polynomial systems. SP$\mathbb{Q}$R works by sampling and reconstructing results over finite fields, in an analogous manner to many state of the art Integration by Parts algorithms for Feynman integrals. This allows SP$\mathbb{Q}$R to effectively overcome expression swell during the construction of Gröbner bases, which in many cases is the major bottleneck in such computations. Benchmarks on state of the art Macaulay resultants show that SP$\mathbb{Q}$R can deliver substantial gains over symbolic computer algebra workflows -- reducing both runtime and memory footprint by multiple orders of magnitude. Likewise when applied to study Feynman integrals, we show how SP$\mathbb{Q}$R can be used to find previously unknown Landau singularities.
