Logic for Information Technology

Book excerpt: This introduction to logic as it applies to information technology is written specifically from the point of view of computer science students. The author's approach adheres to imparting the canonical logic theories--propositional calculus and first-order predicate calculus. The text first introduces a wide range of general logic concepts that are applicable to any variety of logic, followed by detailed clear exposition of the propositional and predicate calculuses and their proof theories. Different methods of validating propositional inferences, as well as the means of determining the adequacy of such methods, are discussed. Algorithmic aspects are stressed, as is the deductive character of logic. The author takes pains throughout the text to eradicate a number of common confusions and misunderstandings, including those between the material conditional (if/then) and logical implication; between syntactical and semantical consequence relations (deducibility vs entailment); and between Use and Mention. All variables used in the predicate calculus are bound by quantifiers, thus avoiding the cumbersome use of variable assignments.