Propositional Logic

Abstract

Logic is a system for rational enquiry and is founded on axioms and inference rules for reasoning. Modern mathematical logic dates back to the works of Frege and Peano late in the 19th century. Examples of logic include classical propositional logic, first-order logic, modal logics and temporal logics. In this chapter, we investigate propositional logic. The focus is on how propositional logic can be used as a tool in the analysis and presentation of system requirements. This requires an investigation of how assertions are formulated and combined, whether assertions imply intended conclusions, and how to mechanically prove certain results from the stated axioms without assigning truth values to the formulas. We include in this chapter only brief and at times informal sketches of the language aspects of logic; however, we quote important results that are sufficient for the study of logic as a specification language.