The Basics of Qualitative Reasoning

Abstract

This part describes the basic approaches used in qualitative reasoning as well as the underlying qualitative calculus and the different dimensions of mapping a quantitative model onto a qualitative one. Additionally, we provide a first classification of these methods. We separate the description of the modeling perspectives of the respective approaches in the next chapter from the detailed discussion of their specific reasoning techniques in chapter II.4 in order to underline the basic principles and their differences. However, also short descriptions of the reasoning mechanisms are provided in the first chapter. We use the following notation: if x denotes a variable or quantity in a numerical model, [x] or x denotes its qualitative equivalent. The same is true for operations: addition becomes ⨁, multiplication ⨂ and so on.⁶