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 la nguage originally suggested by Ya. Yu. Gol'fand. Each Schur ring over Z(n) is uniquely determined by a finite topology L on the set of prime divisors of n and by a family {G(P)}(P is an element of L) Of finite groups satisfying an additional condition.