English

The Chow-Lam Form

Algebraic Geometry 2025-02-20 v2 Combinatorics

Abstract

The classical Chow form encodes any projective variety by one equation. We here introduce the Chow-Lam form for subvarieties of a Grassmannian. By evaluating the Chow-Lam form at twistor coordinates, we obtain universal projection formulas. These were pioneered by Thomas Lam for positroid varieties in the study of amplituhedra, and we develop his approach further. Universal formulas for branch loci are obtained from Hurwitz-Lam forms. Our focus is on computations and applications in geometry.

Cite

@article{arxiv.2401.10795,
  title  = {The Chow-Lam Form},
  author = {Elizabeth Pratt and Bernd Sturmfels},
  journal= {arXiv preprint arXiv:2401.10795},
  year   = {2025}
}

Comments

20 pages

R2 v1 2026-06-28T14:21:45.372Z