Cyclotomy is the study of roots of unity and their algebraic and arithmetic relations. It includes the factorization of 
into cyclotomic polynomials,
cyclotomic fields, and the division of roots of unity into residue classes used in
Gaussian periods.
Cyclotomy
See also
Cyclotomic Field, Cyclotomic Polynomial, Root of UnityExplore with Wolfram|Alpha
References
Washington, L. C. Introduction to Cyclotomic Fields, 2nd ed. New York: Springer-Verlag, 1997.Cite this as:
Weisstein, Eric W. "Cyclotomy." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Cyclotomy.html