Natural language asymmetries and the construction of question answering systems

We discuss the properties of Question Answering Systems, hereafter QAS. We will concentrate on the START system [2 1], pointing out its positive and negative aspects. We propose an approach to efficient QAS based on natural language asymmetries. By natural language asymmetry, we mean a structural relation such as the precede, dominate, asymmetric c-command or sister contain relation, as defined in [9]. Our claim is that efficient QAS are based on these relations, which have been shown to be central in the analysis of linguistic expressions, including questions, see [1], [2], [8], [9], [10], [12], [13], [14]. We start by defining what is a question in current linguistic theory.