Most often projects fail due to the management problems. Some management problems do not happen because of bad managers, but because of risks, which cannot be prevented mentally. Therefore, the project managers, especially who work on big projects, need proactive tools to prevent all possible ambiguous risks. Classical project management solutions try to solve the problem by the probabilistic approach. But this kind of solution does not analyse the all possible scenarios. Therefore experts do not rely on them. In this paper we suggest a theory, which gives an opportunity to analyse all possible scenarios as much as possible.