Zholtkevych, G.Perepelytsya, I.2012-03-082012-03-082011-12Системи управління, навігації та зв’язку. Збірник наукових праць. – Вип. 4 (20). – С. 233 – 238.2073-7394https://ekhnuir.karazin.ua/handle/123456789/5619In this paper we consider a model of system interaction with the environment, which allows us to forget its full protocol from time to time. Mathematical models of such interactions are pre-machines. We showed that the machines can be completely described in terms of some special class of digraphs. An approach to analyzing the structure of pre-machines in terms of their derivatives series is offered.entechnologyinformation technologycomputer Sciencesoftware engineeringfinite state pre-machineprefix marked digraphintervalderivative digraphderivatives serieshierarchic decompositionArticle