The Structure of Schur Rings Over Cyclic Groups of Square-Free Order

We give the complete classification of Schur rings over cyclic groups of square-free order. In this classification we use the topological language originally suggested by Ya. Yu. Gol’fand. Each Schur ring over Zn is uniquely determined by a finite topology L on the set of prime divisors of n and by a family {GP}P ∈ L of finite groups satisfying an additional condition.