Contrary

The contrary function $\overline{\phantom{a}} \colon \mathcal{A} \to \mathcal{L}$ of an ABAF maps each assumption $a$ to its contrary $\overline{a} \in \mathcal{L}$ . If a set of assumptions $S \subseteq \mathcal{A}$ derives $\overline{a}$ , then $S$ attacks $a$ .

Reference

Čyras, K., Fan, X., Schulz, C. & Toni, F. (2018). Assumption-Based Argumentation: Disputes, Explanations, Preferences. In: Baroni, P., Gabbay, D., Giacomin, M. & van der Torre, L. (eds.), Handbook of Formal Argumentation, Vol. 1, Chapter 7, pp. 365–408. College Publications.

Referenced by

Assumption-based Argumentation Framework (ABAF)
Assumption
Attack (ABA)