Decision trees - a powerful tool in mathematical and economic modeling

Oriented graphs belong to a part of Mathematics - Combinatorics called Graph Theory. One of the fundamental terms here is a tree. The tree structures have widespread use not only in Mathematics. They can be used in Decision Theory as data mining tools as well. In the present paper we point out to the use of decision trees as models for financial services, namely, by credit scoring, fraud and churn detection. We also underline the important role of Decision Theory in engineering education.