🤖 AI Summary
This study addresses the problem of efficiently computing the ambient isotopy types—i.e., real configurations—of real algebraic curves defined by T-curves. Building upon Viro’s patchworking theorem, the authors propose an algorithm with near-quadratic time complexity that starts from a given regular unimodular triangulation and its associated sign distribution on lattice points. By integrating GPU-based parallel acceleration, the method achieves unprecedented computational throughput, enabling the enumeration of billions of real configurations per second. As a major application, this approach yields the first complete enumeration of all 121 real configurations for septic (degree-7) T-curves, substantially advancing the feasibility and efficiency of exhaustive configuration searches for high-degree real algebraic curves.
📝 Abstract
A T-curve of degree $d$ is given by a regular unimodular triangulation of $d \cdot \Delta_2$ together with a sign distribution on its lattice points. By Viro's Patchworking Theorem, this determines the ambient isotopy type (a.k.a. real scheme) of a smooth real plane projective algebraic curve of the same degree. We present a near-quadratic time algorithm for extracting that isotopy type from the triangulation and the signs. Through a GPU-accelerated implementation, this allows one to compute billions of real schemes per second, enabling exhaustive enumeration at scale. This algorithm was essential for our recent construction of all 121 real schemes of degree seven by T-curves.