The ab initio calculation of parameters of the Anderson model is illustrated within the framework of a simple, exactly solvable, model of a 3d compound. It is shown how the latter model can be mapped onto a simpler model, by projecting out degrees of freedom, and by including these degrees of freedom implicitly as a renormalization of parameters. For the model studied this approach is shown to be exact in the limit when the projected degrees of freedom correspond to very delocalized electrons.
 

Physical Review B, 41 514-18, 1990.