English

Groups of generalized Moufang type and $\mathbb Z_2$-graded algebras

Rings and Algebras 2026-03-03 v1

Abstract

A pair (G,T)(G,T) is called a faithful odd transposition group if TT is a normal set of involutions generating the group GG and the product of any two distinct elements of TT has odd order. We introduce a special subclass of such groups, a \emph{generalized Moufang group of pp-type} (or GM(p)GM(p)-type), in which the product of any two distinct involutions from TT has a fixed prime order pp. For any such group (G,T)(G,T) and a scalar parameter η\eta in a field F\mathbb F, we construct a non-associative, non-commutative algebra A=AF(G,T,η)A = A_{\mathbb F}(G,T,\eta). We prove that every element of TT considered as an element of the algebra AA, is a primitive semisimple idempotent, defining a Z2\mathbb Z_{2}-grading of AA. The Miyamoto group of AA with respect to TT is isomorphic to G/Z(G)G/Z(G). The algebra AA contains no nontrivial right ideals and, for a specific choice of the parameter η\eta, admits a symmetric left Frobenius form. When GG is a free Burnside group of odd prime period pp extended by an involutory automorphism, the finiteness of GG is equivalent to the finite-dimensionality of AF(G,T,η)A_{\mathbb F}(G,T,\eta), providing a reformulation of the Burnside problem. For p=5p=5 and η=1/3\eta=-1/3, the algebra generated by two idempotents from TT is left-axial and satisfies the Monster-type fusion law M(4/3,4/3)\mathcal{M}(4/3, -4/3). For a prime p>5p>5, the two-generated algebra is also axial, but obeys a more general fusion law. Although the algebra AF(G,T,η)A_{\mathbb F}(G,T,\eta) is initially defined using a group GM(p)GM(p)-type, we show that it admits an intrinsic, group-free characterization by axiomatizing a class of so-called GM(p,η)GM(p,\eta)-type algebras. We prove that every algebra in this class is isomorphic to one arising from the construction above, establishing the equivalence of the two definitions.

Keywords

Cite

@article{arxiv.2603.01988,
  title  = {Groups of generalized Moufang type and $\mathbb Z_2$-graded algebras},
  author = {Ilya Gorshkov},
  journal= {arXiv preprint arXiv:2603.01988},
  year   = {2026}
}