The manual is written based on the materials of the introductory lecture course, which the author gives at the Faculty of Mathematics and Mechanics of St. Petersburg State University to students specializing in applied mathematics and computer science. Particular attention is paid to the connections between the concepts of discrete analysis that arise in different branches of mathematics and modern computer science.

This edition includes many new materials, and therefore the structure of the book has changed: new chapters and paragraphs have appeared. The number of exercises has been increased. The text is supplemented with an alphabetical index and bibliographic recommendations.