On Octonionic Submodules Generated by One Element

The aim of this article is to characterize the octonionic submodules generated by one element, which is very complicated compared with other normed division algebras. To this end, we introduce a novel identity that elucidates the relationship between the commutator and associator within an octonionic bimodule. Remarkably, the commutator can be expressed in terms of the linear combination of associators. This phenomenon starkly contrasts with the quaternionic case, which leads to a unique right octonionic scalar multiplication compatible with the original left octonionic module structure in the sense of forming an octonionic bimodule. With the help of this identity, we get a new expression of the real part and imaginary part of an element in an octonionic bimodule. Ultimately, we obtain that the submodule generated by one element x is \({\mathbb {O}}^5x\) instead of \({\mathbb {O}}x\).