Subgroup ($H$) information
| Description: | $C_{28}$ |
| Order: | \(28\)\(\medspace = 2^{2} \cdot 7 \) |
| Index: | \(21\)\(\medspace = 3 \cdot 7 \) |
| Exponent: | \(28\)\(\medspace = 2^{2} \cdot 7 \) |
| Generators: |
$a^{7}, a^{14}, a^{4}$
|
| Nilpotency class: | $1$ |
| Derived length: | $1$ |
The subgroup is cyclic (hence abelian, nilpotent, solvable, supersolvable, monomial, elementary ($p = 2,7$), hyperelementary, metacyclic, metabelian, a Z-group, and an A-group).
Ambient group ($G$) information
| Description: | $C_{21}:C_{28}$ |
| Order: | \(588\)\(\medspace = 2^{2} \cdot 3 \cdot 7^{2} \) |
| Exponent: | \(84\)\(\medspace = 2^{2} \cdot 3 \cdot 7 \) |
| Derived length: | $2$ |
The ambient group is nonabelian, metacyclic (hence solvable, supersolvable, monomial, and metabelian), and an A-group.
Automorphism information
While the subgroup $H$ is not characteristic, the stabilizer $S$ of $H$ in the automorphism group $\operatorname{Aut}(G)$ of the ambient group acts on $H$, yielding a homomorphism $\operatorname{res} : S \to \operatorname{Aut}(H)$. The image of $\operatorname{res}$ on the inner automorphisms $\operatorname{Inn}(G) \cap S$ is the Weyl group $W = N_G(H) / Z_G(H)$.
| $\operatorname{Aut}(G)$ | $D_{42}:C_6^2$, of order \(3024\)\(\medspace = 2^{4} \cdot 3^{3} \cdot 7 \) |
| $\operatorname{Aut}(H)$ | $C_2\times C_6$, of order \(12\)\(\medspace = 2^{2} \cdot 3 \) |
| $\operatorname{res}(S)$ | $C_2\times C_6$, of order \(12\)\(\medspace = 2^{2} \cdot 3 \) |
| $\card{\operatorname{ker}(\operatorname{res})}$ | \(12\)\(\medspace = 2^{2} \cdot 3 \) |
| $W$ | $C_1$, of order $1$ |
Related subgroups
| Centralizer: | $C_{28}$ | |
| Normalizer: | $C_{28}$ | |
| Normal closure: | $C_{21}:C_{28}$ | |
| Core: | $C_{14}$ | |
| Minimal over-subgroups: | $C_7:C_{28}$ | $C_3:C_{28}$ |
| Maximal under-subgroups: | $C_{14}$ | $C_4$ |
Other information
| Number of subgroups in this conjugacy class | $21$ |
| Möbius function | $1$ |
| Projective image | $D_{21}$ |