A generalised Kummer's Conjecture

Kummer’s Conjecture predicts the rate of growth of the relative class numbers of cyclotomic fields of prime conductor. We extend Kummer’s Conjecture to cyclotomic fields of conductor n, where n is any natural number. We show that the Elliott-Halberstam Conjecture implies that this Generalised Kummer’s Conjecture is true for almost all n but is false for infinitely many n.