On the surface QBF proof systems seem harder to compare to one another since they vary considerably in how they deal with quantification. In particular there's a vast difference between theory systems that generalise from propositional logic, the proof systems that capture the process of CDCL solving and the proof systems that capture the expansion and CEGAR based solvers. And many results do formally show an incomparability in the proof complexity between different systems as we suspect. However, there are a few non-obvious cases where a simulation is possible. In this talk we... more