Adds to the basic taxonomic structure of the knowledge-base. Sets are described by lists whose atomic elements are (names of) the members of the sets and whose sublists are subsets of the set. The set forming the root of the taxonomy (set1 in the example below) must exist in the knowledge base when the :taxonomy form is asserted.
The sets and elements in a :taxonomy form must have uniquely designating names.
(:taxonomy (set1 (set2 frame1 frame2) (set3 frame3)))
requires that set1 already exists in the knowledge base; asserts that set2 and set3 are subsets of set1, not necessarily disjoint; that frame1 and frame2 are elements of set2; and that frame3 is an element of set3.