Collective Attack

A collective attack $(T, h) \in R$ of a SetAF $S = (A, R)$ is a joint attack of all arguments in $T$ on $h$ ; it succeeds only if every argument in $T$ is accepted.

Reference

Nielsen, S.H. & Parsons, S. (2006). A Generalization of Dung's Abstract Framework for Argumentation: Arguing with Sets of Attacking Arguments. In: Argumentation in Multi-Agent Systems (ArgMAS 2006), LNCS 4766, pp. 54–73. Springer.