9. The method as described in claim 7 , wherein: the step (a) comprises introducing two or three patent indices; and the step (d) comprises: (i) selecting one of said sub-spaces; (ii) selecting a patent document whose patent indices belong to the selected sub-space; (iii) assigning a color to the selected sub-space according to a color model, having respectively two or three input components whose mixture produces said color, wherein values of the components of the color model are equal to the respective values of patent indices.
7. The method as described in claim 5 , further comprising visualizing the quality of the patent document, comprising: (d) assigning a color to each of said sub-spaces within said hyperspace such that at least one said sub-space has a color, which is different from colors of other said sub-spaces; and (e) assigning a color to the quality of the patent document, which is the same as the color of the sub-space to which said patent indices characterizing the patent document belong.