the notion of an argumentation framework *expansion* has been introduced by Baumann and Brewka [@baumann2010expanding]. A concise introduction and overview of expansions is presented by Baumann and Woltran [@8209878]. The general concept of an argumentation framework expansion can be defined as follows.

An argumentation framework $AF'$ is an expansion of an argumentation framework $AF = (AR, Attacks)$ ($AF \preceq_E AF'$) iff $AF' = (AR \cup AR', Attacks \cup Attacks')$, where $AR' \cap AR =Attacks' \cap Attacks = \emptyset$.

Several expansion types have been defined in the literature. In the context of this paper, the notion of a *normal* expansion is of relevance.

An expansion $AF'$ of an argumentation framework $AF$ is *normal* ($AF \preceq_N AF'$) iff $\forall a,b: ((a, b) \in Attacks' \rightarrow a \in AR' \lor b \in AR')$.

In words, a normal expansion of an argumentation framework adds additional arguments to the framework that can attack and be attacked by any other argument but does neither remove existing arguments nor change attack relations (neither add nor remove) between existing arguments.

Rational Argumentation-based Choice Function {#preferences}
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In this section, we define the concept of *economically rational argumentation-based choice functions* and, in this context, provide a brief overview of 