The algebraic and geometric classification of noncommutative Jordan algebras
Hani Abdelwahab, Kobiljon Abdurasulov, Ivan Kaygorodov
TL;DR
This work develops a framework to algebraically classify finite-dimensional noncommutative Jordan algebras by leveraging the Jordan algebra classification, via the correspondence with generic Poisson--Jordan structures. It delivers detailed algebraic classifications in low dimensions: 3D complex noncommutative Jordan, Kokoris, and standard algebras, plus 4D nilpotent cases, accompanied by explicit families and rigid instances. The geometric classification analyzes varieties of these algebras, identifying their dimensions, irreducible components, rigid algebras, and concrete degeneration patterns, thereby describing the orbit closures generating each component. Overall, the paper provides a unified approach to both algebraic and geometric aspects of noncommutative Jordan-type algebras and related Poisson-like structures, highlighting the rich landscape of degenerations and rigidity in small dimensions.
Abstract
In this paper, we develop a method to obtain the algebraic classification of noncommutative Jordan algebras from the classification of Jordan algebras of the same dimension. We use this method to obtain the algebraic classification of complex $3$-dimensional noncommutative Jordan algebras. As a byproduct, we obtain the classification of complex $3$-dimensional Kokoris, standard, generic Poisson, and generic Poisson--Jordan algebras; and also complex $4$-dimensional nilpotent Kokoris and standard algebras. In addition, we consider the geometric classification of varieties of cited algebras, that is the description of its irreducible components.
