The concept of a ''personal book''

Some recent investigations concerning automatic generation and traversal of hypertext networks can be considered as steps toward creating intelligent agents able to generate new coherent texts in responce to a user's query. These texts, composed of fragments of full texts, can be called ''personal books''. Ensuring coherence of the automatically constructed text is a very important problem because the relevance of separate text fragments to the query is not a sufficient condition to avoid long arrays of chaotic and unperceptive information. Some theories of discourse assume that a coherent, ordered sequence of fragments emerges from cohesive ties reflecting the semantic similarity of successive fragments in the sequence with the preceding ones. In this paper we describe the criteria for the automatic selection of the next fragment that increases the general coherence of the composed text.