In this paper we introduce a novel semantics, called defense semantics, for Dung's abstract argumentation frameworks in terms of a notion of (partial) defence, which is a triple encoding that one argument is (partially) defended by another argument via attacking the attacker of the first argument. In terms of defense semantics, we show that defenses related to self-attacked arguments and arguments in 3-cycles are unsatifiable under any situation and therefore can be removed without affecting the defense semantics of an AF. Then, we introduce a new notion of defense equivalence of AFs, and compare defense equivalence with standard equivalence and strong equivalence, respectively. Finally, by exploiting defense semantics, we define two kinds of reasons for accepting arguments, i.e., direct reasons and root reasons, and a notion of root equivalence of AFs that can be used in argumentation summarization.

翻译：本文针对Dung的抽象论证框架，基于（部分）辩护的概念引入了一种新的语义——辩护语义。该语义采用三元编码形式，表征一个论元通过攻击另一论元的攻击者而（部分）地受到该论元辩护。基于辩护语义，我们证明在任何情况下，与自攻击论元和三元环中论元相关的辩护均不可满足，因此可在不影响论证框架辩护语义的前提下移除这些辩护。随后，我们提出论证框架的辩护等价新概念，并将其分别与标准等价和强等价进行比较。最后，通过挖掘辩护语义，我们定义了两种接受论元的理由（即直接理由与根本理由），以及可用于论证摘要的论证框架根本等价概念。