English

Split spin factor algebras

Rings and Algebras 2021-07-19 v2 Group Theory

Abstract

Motivated by Yabe's classification of symmetric 22-generated axial algebras of Monster type, we introduce a large class of algebras of Monster type (α,12)(\alpha, \frac{1}{2}), generalising Yabe's III(α,12,δ)\mathrm{III}(\alpha,\frac{1}{2}, \delta) family. Our algebras bear a striking similarity with Jordan spin factor algebras with the difference being that we asymmetrically split the identity as a sum of two idempotents. We investigate the properties of this algebra, including the existence of a Frobenius form and ideals. In the 22-generated case, where our algebra is isomorphic to one of Yabe's examples, we use our new viewpoint to identify the axet, that is, the closure of the two generating axes.

Keywords

Cite

@article{arxiv.2104.11727,
  title  = {Split spin factor algebras},
  author = {J. McInroy and S. Shpectorov},
  journal= {arXiv preprint arXiv:2104.11727},
  year   = {2021}
}

Comments

17 pages. The results in Section 5 have been simplified and strengthened. A new section has been added to deal with a family of exceptional algebras which arise for $\alpha=-1$

R2 v1 2026-06-24T01:28:13.109Z