Preliminaries

Abstract

This chapter recalls the formal background which provides the formal base this thesis is built upon. We start by introducing the running example, a variant of the iconic example from nonmonotonic reasoning speaking about birds and penguins with respect to their ability to fly. This example is then used to illustrate the stepwise recallection of the necessary preliminaries in propositional logic and classical entailment (Section 2.1), conditionals and knowledge bases (Section 2.2), and nonmonotonic inference (Section 2.3).