On the conjecture of Kashuba and Mathieu about free Jordan algebras

Abstract

Kashuba and Mathieu proposed a conjecture on vanishing of Lie algebra homology, implying a description of the $G{L}_d$-module structure of the free $d$-generated Jordan algebra. Their conjecture relies on a functorial version of the Tits--Kantor--Koecher construction that builds Lie algebras out of Jordan algebras. In this note, we summarize new intricate computational data concerning free Jordan algebras and explain why, despite a lot of overwhelmingly positive evidence, the conjecture of Kashuba and Mathieu is not true.

18 pages. arXiv admin note: substantial text overlap with arXiv:2503.16074