With gestures toward earlier work by Phan Minh Dung (1995), Gregor Betz constructs a model of belief change based on “dialectical structures” of linked arguments (Betz 2013). Sentences and their negations are represented as digits positive and negative, arguments as ordered sets of sentences, and two forms of links between arguments: an attack relation in which a conclusion of one argument contradicts a premise of another and support relations in which the conclusion of one argument is equivalen