Inconsistent requirements: an argumentation view

We present a logical framework for reasoning about inconsistent requirements in the context of the multi-viewpoint requirements engineering process. In order to analyse the sources of inconsistencies and to reason with inconsistent requirements, we present an argumentation view of the requirements. Intuitively, argumentation is a tool for reasoning with inconsistent knowledge: requirements are defined in terms of arguments (a conclusion with its support); then, a class of acceptable arguments is built (arguments with no counterarguments). We propose to characterize different classes of requirements which are ordered: from weakly confident to strongly confident (i.e. consistent). We present inference rules to build intra and inter-viewpoint reasoning. Inference rules are issued from the classes of requirements. We show how this work is useful for the requirements engineers to analyse inconsistent fragments of requirements.