On commuting U-operators in Jordan algebras
Recently J. A. Anquela, T. Cortés, and H. P. Petersson proved
that for elements x, y in a non-degenerate Jordan algebra J, the relation
x o y = 0 implies that the U-operators of x and y commute: Ux Uy
= Uy Ux.
We show that the result may be not true without the assumption on
non-degeneracy of J. We give also a simpler proof of the mentioned result
in the case of linear Jordan algebras, that is, when char F ≠ 2.
I. Shestakov < ivan.shestakov@gmail.com >