A collective defence against grouped attacks for weighted abstract argumentation frameworks

Adding weights or preferences to Abstract Argumentation Frameworks can help disentangle semantics from otherwise all-equivalent attacks. Having such information makes possible to distil the set of found extensions by reducing their number. In this work we provide a new definition of weighted defence: according to it, all the attacks from an argument to a set of arguments are considered with a single global weight, i.e., attacks are grouped together. This provides a coherent view w.r.t. defence, which is usually “collective” in the literature. Moreover, we model weighted defences from related works in the same algebraic framework: this allows us to compare all the different proposals together.