Gentzen-type systems, resolution and tableaux

We show that both the tableaux and the resolution methods can be understood as attempts to exploit the power of cut-elimination theorems in Gentzen-type calculi. Another, related goal is to provide a purely syntactic basis for both methods (in contrast to the semantic proofs concerning resolution that can be found in the textbooks). This allows the use of a fruitful combination of the methods and might be helpful in generalizing them to other logics.