English

Reciprocity via Reciprocants

Number Theory 2023-09-12 v2

Abstract

The determinant of a skew-symmetric matrix has a canonical square root given by the Pfaffian. Similarly, the resultant of two reciprocal polynomials of even degree has a canonical square root given by their reciprocant. Computing the reciprocant of two cyclotomic polynomials yields a short and elegant proof of the Law of Quadratic Reciprocity.

Keywords

Cite

@article{arxiv.2309.02512,
  title  = {Reciprocity via Reciprocants},
  author = {Matthew Baker},
  journal= {arXiv preprint arXiv:2309.02512},
  year   = {2023}
}

Comments

10 pages. v2: Rewrote Appendix B, fixed miscellaneous typos

R2 v1 2026-06-28T12:13:33.424Z