The Lie algebra f4(Os) (split f4) with Mathematica

We present in this paper all the details for a complete description of the Lie algebra a in the split case at any characteristic. We finish with the determination of the expression of a generic element of this algebra. First of all is necessary to implement its quadratic Jordan structure (see the O. Loss' server http://mathematik.uibk.ac.at/jordan for our preprint). We write in this file only the computational details.