A cyclotomic extension of a field 
is a field extension obtained by adjoining a root of unity
to 
.
When 
and the adjoined root is a primitive 
th root of unity 
, the resulting extension 
is a cyclotomic field
and is an Abelian Galois extension of 
.
Cyclotomic Extension
See also
Cyclotomic Field, Extension Field, Galois Extension Field, Root of UnityExplore with Wolfram|Alpha
References
Fröhlich, A. and Taylor, M. Ch. 6 in Algebraic Number Theory. New York: Cambridge University Press, 1991.Cite this as:
Weisstein, Eric W. "Cyclotomic Extension." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/CyclotomicExtension.html