A New Method of Verification of Functional Programs

In the paper the problem of verification of functional programs (FPs) over strings is considered, where specifications of properties of FPs are defined by other FPs, and a FP S1 meets a specification defined by another FP S2 iff a composition of functions defined by the FPs S1 and S2 is equal to the constant 1. We introduce a concept of a state diagram of a FP, and reduce the verification problem to the problem of an analysis of the state diagrams of FPs. The proposed approach is illustrated by the example of verification of a sorting program.