3.2 The knowledge structure
The analyzed sentences are stored in a knowledge structure, which is designed to guarantee no details of a sentence are lost: After analyzing and storing a given sentence, an integrity system retrieves the sentence from the knowledge structure and compares it with the original sentence. Any loss of detail is considered to be a violation of the system's integrity.
By keeping track of changes – rather than overwriting knowledge – a history is build in the knowledge structure. Therefore, it is able to e.g. differentiate past tense from present tense.