English

Quadratic forms classify products on quotient ring spectra

Algebraic Topology 2016-01-20 v1

Abstract

We construct a free and transitive action of the group of bilinear forms Bil(I/I^2[1]) on the set of R-products on F, a regular quotient of an E-infinity ring spectrum R with F_* \cong R_*/I. We show that this action induces a free and transitive action of the group of quadratic forms QF(I/I^2[1]) on the set of equivalence classes of R-products on F. The characteristic bilinear form of F introduced by the authors in a previous paper is the natural obstruction to commutativity of F. We discuss the examples of the Morava K-theories K(n) and the 2-periodic Morava K-theories K_n.

Keywords

Cite

@article{arxiv.1004.0964,
  title  = {Quadratic forms classify products on quotient ring spectra},
  author = {Alain Jeanneret and Samuel Wuethrich},
  journal= {arXiv preprint arXiv:1004.0964},
  year   = {2016}
}

Comments

29 pages

R2 v1 2026-06-21T15:07:17.198Z