Mathematical considerations regarding the stability of trace elements systems by polynomial regressions

Mathematical model which describes the stability conditions of the human body considered as a big cybernetic system that lives in the normal condition by feed-back is generalised. Starting by a linear approximation, stability's conditions in the polynomial case of dependencies between trace elements determined in organs of the human body is generalised. This model was tested on traces of: Fe, Zn and Co. These elements were determined in breast tissues samples which have different diseases. (author)