English

Tur\'an and Ramsey problems for alternating multilinear maps

Combinatorics 2023-08-16 v4 Algebraic Geometry Group Theory

Abstract

Guided by the connections between hypergraphs and exterior algebras, we study Tur\'an and Ramsey type problems for alternating multilinear maps. This study lies at the intersection of combinatorics, group theory, and algebraic geometry, and has origins in the works of Lov\'asz (Proc. Sixth British Combinatorial Conf., 1977), Buhler, Gupta, and Harris (J. Algebra, 1987), and Feldman and Propp (Adv. Math., 1992). Our main result is a Ramsey theorem for alternating bilinear maps. Given s,tNs, t\in \mathbb{N}, s,t2s, t\geq 2, and an alternating bilinear map f:V×VUf:V\times V\to U with dim(V)=st4\dim(V)=s\cdot t^4, we show that there exists either a dimension-ss subspace WVW\leq V such that dim(f(W,W))=0\dim(f(W, W))=0, or a dimension-tt subspace WVW\leq V such that dim(f(W,W))=(t2)\dim(f(W, W))=\binom{t}{2}. This result has natural group-theoretic (for finite pp-groups) and geometric (for Grassmannians) implications, and leads to new Ramsey-type questions for varieties of groups and Grassmannians.

Keywords

Cite

@article{arxiv.2007.12820,
  title  = {Tur\'an and Ramsey problems for alternating multilinear maps},
  author = {Youming Qiao},
  journal= {arXiv preprint arXiv:2007.12820},
  year   = {2023}
}

Comments

22 pages, no figures. This is the published version

R2 v1 2026-06-23T17:23:43.172Z