Arguing coalitions in abstract argumentation

In this paper, we are interested in different ways in which agents can collaborate in abstract agent argumentation. First, if arguments are accepted when they are put forward by more than one agent, then agents can put forward arguments from other agents of the coalition. Second, agents can put forward arguments to defend argu- ments from other agents of the coalition. For example, in expert opinion, a domain expert can put forward an argument defending an argument made by a politician, even when the politician cannot judge the correctness of the argument. Third, agents from a coalition can collectively defend an argument they share, without being able to defend the argument individually. In this paper, we formalize the different kinds of collaboration in abstract agent argumentation, and we illustrate the coalition for- mation with a case study in political debate.