This book provides a good introduction to the classical elementary number theory and the modern algorithmic number theory, and their applications in computing and information technology, including computer systems design, cryptography and network security. In this second edition proofs of many theorems have been provided, further additions and corrections were made.
This the Second Edition of Lewis and Papadimtriou's best-selling theory of computation text. In this substantially modified edition, the authors have enhanced the clarity of their presentation by making the material more accessible to a broader undergraduate audience with no special mathematical experience. For example, long proofs have been simplified and/or truncated, with their more technical points delegated to exercises, advanced material is presented in an informal and friendly manner, and problems follow each section to check student comprehension. The book continues to comprise a mathematically sound introduction to the classical and contemporary theory of computation, and provide deep insights into the fundamental paradigms of computer science.