This field contains all nth roots of unity and is the splitting field of the nth cyclotomic polynomial over Q. The field extension Q(exp(2πi/n))/Q has degree φ(n) and its Galois group is naturally isomorphic to the multiplicative group of units of the ring Z/nZ. Ce corps contient toutes les racines n-ièmes de l'unité et est le corps de décomposition sur ℚ du polynôme cyclotomique d'indice n. L'extension de corps F n / Q
