Abstract
The paper deals with an investigation and modeling of dialogue and dialogue transactions. An ontological model of human dialogue interaction, underlying follow-up reasoning, is obtained on the basis of analysis of human-human dialogues and illustrated by one of Plato's dialogue Protagoras. In the sequel, attention is focused on one type of human-human dialogues, called erotetic dialogue and on the structure of erotetic dialogue transaction from the viewpoint of knowledge interchange within the transaction. A spectrum of formal models, oriented towards discovering the inner logical structure of erotetic transaction is offered. The distinguishing feature of all models is their orientation on language-independent entities representing declarative knowledge associated with a transaction's elements.