Reasoning over Attack-incomplete AAFs in the Presence of Correlations

Attack-Incomplete Abstract Argumentation Frameworks (att-

iAAFs) are a popular extension of AAFs where attacks are

marked as uncertain when they are not unanimously per-

ceived by different agents reasoning on the same arguments.

We here extend att-iAAFs with the possibility of specifying

correlations involving the uncertain attacks. This feature sup-

ports a unified and more precise representation of the differ-

ent scenarios for the argumentation, where, for instance, it

can be stated that an attack α has to be considered only if an

attack β is considered, or that α and β are alternative, and

so on. In order to provide a user-friendly language for spec-

ifying the correlations, we allow the argumentation analyst

to express them in terms of a set of elementary dependen-

cies, using common logical operators (namely, OR , NAND ,

CHOICE , ⇒). In this context, we focus on the problem of

verifying extensions under the possible perspective, and study

the sensitivity of its computational complexity to the forms of

correlations expressed and the semantics of the extensions.