Computer Security: Art and Science

Chapter 34. Symbolic Logic^[1]

This chapter provides background on various types of logic. One can use symbols to represent data and functions to create formulas using the rules of logic. Then the rules of a logic system allow the analyst to reason about formulas made out of the symbols.

Propositional Logic

Propositional logic, also called the propositional calculus, is based on propositions, or atomic, declarative sentences that can be shown to be either true or false (but not both). Examples of such statements are “The sky is blue today,” “Nine divided by 3 equals 3,” and “All people like chocolate.” Questions, and statements such as “Let's go!” and “Here's hoping for the best,” are not considered declarative because they cannot be argued to be ...