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Psi-calculi is a parametric framework for process calculi similar to popular pi-calculus extensions such as the explicit fusion calculus, the applied pi-calculus and the spi calculus. Remarkably, machine-checked proofs of standard algebraic and congruence properties of bisimilarity apply to every instance of the framework.

The contribution of this licentiate thesis is to significantly extend the applicability and expressiveness of psi-calculi by incorporating several advanced language features into the framework: broadcasts, higher-order communication, generalised pattern matching, sorts and priorities. The extensions present several interesting technical challenges, such as negative premises. The machine-checked proofs for standard results about bisimilarity are generalised to each of these new settings, and the proof scripts are freely available online.

Concurrent systems, i.e., systems of parallel processes, are nearly ubiquitous and verifying the correctness of such systems is becoming an important subject. Many formalisms were invented for such purpose, however, new types of systems are introduced and there is a need for handling larger systems. One examples is wireless sensor networks that are being deployed in increasing numbers in various areas; and in particular safety-critical areas, e.g., bush fire detection. Thus, ensuring their correctness is important.

A process calculus is a formal language for modeling concurrent systems. The pi-calculus is a prominent example of such a language featuring message-passing concurrency. Psi-calculi is a parametric framework that extends the pi-calculus with arbitrary data and logics. Psi-calculi feature a universal theory with its results checked in an automated theorem prover ensuring their correctness.

In this thesis, we extend psi-calculi expressiveness and modeling precision by introducing a sort system and generalised pattern matching. We show that the extended psi-calculi enjoy the same meta-theoretical results.

We have developed the Pwb, a tool for the psi-calculi framework. The tool provides a high-level interactive symbolic execution and automated behavioral equivalence checking. We exemplify the use of the tool by developing a high-level executable model of a data collection protocol for wireless sensor networks.

We are the first to introduce a session types based system for systems with unreliable communication. Remarkably, we do not need to add specific extensions to the types to accommodate such systems. We prove the standard desirable properties for type systems hold also for our type system.