On the Relative Expressiveness of Argumentation Frameworks, Normal Logic   Programs and Abstract Dialectical Frameworks
  We analyse the expressiveness of the two-valued semantics of abstract argumentation frameworks, normal logic programs and abstract dialectical frameworks. By expressiveness we mean the ability to encode a desired set of two-valued interpretations over a given propositional signature using only atoms from that signature. While the computational complexity of the two-valued model existence problem for all these languages is (almost) the same, we show that the languages form a neat hierarchy with respect to their expressiveness. 
Hannes Strass
cs.AI cs.LO