Argumentation stages with structured arguments
A defeat status assignment (obeying the structural constraints) is an argumentation stage if the following holds:
An argument ? is defeated if and only if
1. (direct defeat) there is an undefeated argument ? in A that attacks ?,
or
2. (indirect defeat) there is a defeated argument ? that is an initial or broadening of ?.
? For unstructured arguments, 2 is trivially false.