Linear recursion with constant coefficients. The Master theorem.
Graphs. Euler circuits, Hamilton cycles. Trees. Graph coloring. Planar graphs. Euler’s polyhedron formula, Kuratowski's theorem. Bipartite graphs. Hall's marriage theorem. Augmenting alternating paths. Transversals.
Integer arithmetic. Modular arithmetic. Euler’s ɸ- and Möbius’ μ-function. Euler’s theorem and Fermat’s little theorem.
Permutations. Cycle notation. Conjugated permutations. Even and odd permutations.
Basic group theory. Order of group elements and group. Cyclic groups. The symmetric group. Subgroups, cosets. Lagrange’s theorem. Group actions on sets. Burnside’s lemma.
Rings and fields. Factorization of polynomials. Irreducible polynomials. Finite fields.
Error correcting linear binary codes. RSA cryptosystem. Primality tests.