Fuzzy set theory, Fuzzy logic

This paper should serve as an introduction to natural deduction modelling that is based on fuzzy type theory. First the theory for the topic is explained, one of the classical logic systems is chosen (Predicate logic) then introduction to fuzzy logic is given and then fuzzy type theory is introduced and the reasons why it was chosen for this paper are explained. In the practical part of the paper there is an example on which the suggestions of how to possibly expand Prolog language with fuzzy type theory features are explained. The practical example is demonstrated on a criminal case.