**S****p****ecific Objectives of course:**

The focus of the course is on study of the fundamental properties of integers and develops ability to prove basic theorems. The specific objectives include study of division algorithm, prime numbers and their distributions, Diophantine equations, and the theory of congruences.

**Course Outline:**

**P****reliminaries:**

Well-ordering principle. Principle of finite induction.

**Divisibility theory:**

The division algorithms. Basis representation theorem. Prime and composite numbers. Canonical decomposition. The greatest common divisor. The Euclidean algorithm. The fundamental theorem of arithmetic. Least common multiple.

**L****inear Diophantine equations:**

Congruences. Linear congruences. System of linear congruences. The Chinese remainder theorem. Divisibility tests. Solving polynomial congruences. Fermat’s and Euler’s theorems. Wilson’s theorem.

**A****r****ithmetic functions:**

Euler’s phi-function. The functions of J and sigma. The Mobius function. The sieve of Eratosthenes. Perfect numbers. Fermat and Mersenne primes.

**P****rimitive Roots and Indices:**

The order of an integer mod n. Primitive roots for primes. Composite numbers having primitive roots.

**Quadratic residues:**

Legendre symbols and its properties. The quadratic reciprocity law. Quadratic congruences with composite moduli. Pythagorean triples. Representing numbers as sum of two squares.