A finite group $G$ is **nilpotent** if it is a direct product of $p$-groups. Equivalently, all Sylow subgroups of $G$ are normal. Equivalently, $G$ has a central series
\[\{1\}=G_0 \lhd G_1 \lhd G_2 \lhd \ldots \lhd G_k = G\]
a nested sequence of normal subgroups with $[G,G_{i+1}] \leq G_i$.

The smallest such $k$ is the **nilpotency class** of $G$. It is $0$ for $C_1$, $1$ for non-trivial abelian groups, and $\geq 2$ for all other nilpotent groups. By convention, one can define the nilpotency class of a non-nilpotent group to be $-1$.

Nilpotent groups are closed under subgroups and quotients (but not extensions), and are solvable, supersolvable and monomial.

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- Review status: beta
- Last edited by John Jones on 2019-09-06 01:49:44

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- 2019-09-06 01:49:44 by John Jones
- 2019-05-23 18:32:50 by John Jones
- 2019-05-23 18:31:00 by John Jones
- 2019-05-22 20:05:44 by Tim Dokchitser
- 2019-05-22 19:36:14 by Tim Dokchitser

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