Proving well-formedness of interface specifications

Automated software verification systems, that try to prove the correctness of a program, use specifications in the code as a base to verify said program. When this specification includes calls to sideeffect free methods, the verification system might want to use the specification of these side-effect free methods to have more information available for its correctness proofs. Unfortunately, the specifications of these side-effect free methods can be ill-formed, which can introduce unsoundness to the verification system. For some sources of this unsoundness, like unfeasible postconditions, solutions are already found and implemented. Other ill-formedness issues, like non well-founded recursion in specifications, are known and met by syntactic rules that solve them, but are stricter than they need to be, thus disallowing a range of specifications, that are not ill-formed at all. The goal of this thesis was to find proof obligations that prove, that a given method specification or class invariant is well-formed and thus safe to use for correctness proofs. These proof obligations were then implemented in the automated software verification system Boogie to filter out non well-formed specifications.