Let an ideal class be in if it contains an Ideal whose th power is Principal. Let be an Odd Integer and define by . Then . If and , then .
References
Ireland, K. and Rosen, M. ``Herbrand's Theorem.'' §15.3 in A Classical Introduction to Modern Number
Theory, 2nd ed. New York: Springer-Verlag, pp. 241-248, 1990.