Theory of Active Perception uses a finite number of elements combined into groups of different levels according to certain laws. We call these elements filters-operators. A filter is a conditional mathematical value, endowed with other values, including absolute. Thus, a filter can be evaluated using the mass of the image which has gone through that filter.
Operators, however, have nothing to do with mathematics. An operator occurs (takes a value) with respect to filters. In fact, it is the same element as the filter — labeled in the same way, but no longer representing mathematical values. Rather, those are letters that are meaningful per se.
With these elements, TAPe describes the very shift from mathematics to language and back again — exactly what we call languagemathics that the human brain operates on.