Abstract
Understanding a text, in the context of machine understanding , refers to understanding objects from the text category. The text category T, members of which are composed from the basic linguistic elements—the letters—members of the letter category, was introduced in the previous our book [103]. The letter category, described in the previous chapter, is in some aspects similar to the visual symbol category (derived from the sign category). However, understanding objects from the letter category is different from understanding objects from the visual symbol category such as the electronic symbol category. For this reason instead of understanding the letter category machine understanding refers to understanding the text category, members of which are composed from the letters.