An abstract framework for structured arguments is presented that
instantiates Dung’s (1995) abstract argumentation frameworks. Arguments
are defined as inference trees formed by applying two kinds of inference
rules: strict and defeasible rules. This naturally leads to three ways of
attacking an argument: attacking a premise, attacking a conclusion and
attacking an inference. To resolve such attacks, preferences may be used,
which leads to three corresponding kinds of defeat: undermining, rebutting
and undercutting defeat. The nature of the inference rules, the structure
of the logical language on which they operate and the origin of the
preferences are, apart from some basic assumptions, left unspecified.

The resulting framework integrates work of Pollock, Vreeswijk and others
on the structure of arguments and the nature of defeat, and extends it in
several respects. Various rationality postulates hold for the framework,
and several existing approaches are a special case
of the framework, including assumption-based argumentation, Deflog and
argumentation in classical logic.