Abstract
Let KO(\bm{C}Pm) be the KO-ring of the complex projective space \bm{C}Pm. By means of methods of rational D-series [{4}], a formula for the J-orders of elements of KO(\bm{C}Pm) is given. Explicit formulas are given for computing the J-orders of the canonical generators of KO(\bm{C}Pm) and the J-order of any complex line bundle over \bm{C}Pm