cyclotomic extensionCyclotomicExtension2005-02-23 14:47:082005-02-23 14:47:08Definitionroot of unity% this is the default PlanetMath preamble. as your knowledge
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\newcommand{\Rats}{\mathbb{Q}}\begin{defn}
Let $K$ be a field and let $\overline{K}$ be a fixed algebraic closure of $K$. A cyclotomic extension of $K$ is an extension field of the form $K(\zeta)$ where $\zeta\in \overline{K}$ is a root of unity.
\end{defn}