Properties

Label 128.2144.8.h1
Order $ 2^{4} $
Index $ 2^{3} $
Normal Yes

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Subgroup ($H$) information

Description:$Q_{16}$
Order: \(16\)\(\medspace = 2^{4} \)
Index: \(8\)\(\medspace = 2^{3} \)
Exponent: \(8\)\(\medspace = 2^{3} \)
Generators: $\left(\begin{array}{rr} 1 & 11 \\ 0 & 7 \end{array}\right), \left(\begin{array}{rr} 1 & 2 \\ 0 & 1 \end{array}\right)$ Copy content Toggle raw display
Nilpotency class: $3$
Derived length: $2$

The subgroup is normal, a semidirect factor, nonabelian, a $p$-group (hence nilpotent, solvable, supersolvable, monomial, elementary, and hyperelementary), and metacyclic (hence metabelian).

Ambient group ($G$) information

Description: $C_{16}:C_2^3$
Order: \(128\)\(\medspace = 2^{7} \)
Exponent: \(16\)\(\medspace = 2^{4} \)
Nilpotency class:$4$
Derived length:$2$

The ambient group is nonabelian, a $p$-group (hence nilpotent, solvable, supersolvable, monomial, elementary, and hyperelementary), and metabelian.

Quotient group ($Q$) structure

Description: $C_2^3$
Order: \(8\)\(\medspace = 2^{3} \)
Exponent: \(2\)
Automorphism Group: $\PSL(2,7)$, of order \(168\)\(\medspace = 2^{3} \cdot 3 \cdot 7 \)
Outer Automorphisms: $\PSL(2,7)$, of order \(168\)\(\medspace = 2^{3} \cdot 3 \cdot 7 \)
Nilpotency class: $1$
Derived length: $1$

The quotient is abelian (hence nilpotent, solvable, supersolvable, monomial, metabelian, and an A-group), a $p$-group (hence elementary and hyperelementary), and rational.

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)$$C_2^4.C_2^6.C_2^2$
$\operatorname{Aut}(H)$ $D_8:C_2$, of order \(32\)\(\medspace = 2^{5} \)
$\operatorname{res}(S)$$D_8:C_2$, of order \(32\)\(\medspace = 2^{5} \)
$\card{\operatorname{ker}(\operatorname{res})}$\(64\)\(\medspace = 2^{6} \)
$W$$D_8$, of order \(16\)\(\medspace = 2^{4} \)

Related subgroups

Centralizer:$C_2\times C_4$
Normalizer:$C_{16}:C_2^3$
Complements:$C_2^3$
Minimal over-subgroups:$C_2\times Q_{16}$$D_8:C_2$$\SD_{32}$
Maximal under-subgroups:$C_8$$Q_8$

Other information

Number of subgroups in this autjugacy class$2$
Number of conjugacy classes in this autjugacy class$2$
Möbius function$-8$
Projective image$C_2^2\times D_8$