Transformation techniques for constraint logic programs with applications to protocol verification

The contribution of this thesis consists in the extension of the techniques for the transformation of constraint logic programs and the development of methods for the application of these techniques to the proof of temporal properties of parameterized protocols. In particular, we first introduce a method for proving automatically the total correctness of an unfold/fold transformation by solving linear equations and inequations over the natural numbers. We also propose a transformation-based method for proving first order properties of constraint logic programs which manipulate finite lists of real or rational numbers. Then, we extend the standard folding transformation rule by introducing two variants of this rule. The first variant combines the folding rule with the clause splitting rule for obtaining a more powerful folding rule. The second variant is tailored to the elimination of the existential variables occurring in a clause. For the standard folding rule and its two variants we develop the corresponding algorithms for automating their application. Finally, we propose a program transformation framework for proving temporal properties of parameterized protocols. Using this framework we encode the protocols and the temporal properties we want to prove as logic programs, and then we use the unfold/fold transformation technique for proving whether or not the properties holds