English

An Analogue of Gauss Composition for Binary Cubic Forms

Number Theory 2019-12-11 v1

Abstract

Over 200 years ago, Gauss discovered a composition law on the SL2(Z)SL_2({\mathbb Z})-equivalence classes of primitive binary quadratic forms. Since then, bijections of classes of binary forms have been found with ideal class groups of quadratic rings. This paper uses one such bijection given by Bhargava, relating classes of projective binary cubic forms to the 33-torsion of an ideal class group, to find an explicit form for a cubic analogue of Gaussian composition.

Cite

@article{arxiv.1912.04324,
  title  = {An Analogue of Gauss Composition for Binary Cubic Forms},
  author = {Benjamin Nativi},
  journal= {arXiv preprint arXiv:1912.04324},
  year   = {2019}
}
R2 v1 2026-06-23T12:40:36.139Z