Properties

Label 128.68.8.e1.a1
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: $ac^{6}, b^{2}c$ Copy content Toggle raw display
Nilpotency class: $3$
Derived length: $2$

The subgroup is characteristic (hence 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: $D_8:C_8$
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: $C_8$
Order: \(8\)\(\medspace = 2^{3} \)
Exponent: \(8\)\(\medspace = 2^{3} \)
Automorphism Group: $C_2^2$, of order \(4\)\(\medspace = 2^{2} \)
Outer Automorphisms: $C_2^2$, of order \(4\)\(\medspace = 2^{2} \)
Nilpotency class: $1$
Derived length: $1$

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

Automorphism information

Since the subgroup $H$ is characteristic, the automorphism group $\operatorname{Aut}(G)$ of the ambient group acts on $H$, yielding a homomorphism $\operatorname{res} : \operatorname{Aut}(G) \to \operatorname{Aut}(H)$. The image of $\operatorname{res}$ on the inner automorphism group $\operatorname{Inn}(G)$ is the Weyl group $W = G / Z_G(H)$.

$\operatorname{Aut}(G)$$C_4^2.C_2^4$, of order \(256\)\(\medspace = 2^{8} \)
$\operatorname{Aut}(H)$ $D_8:C_2$, of order \(32\)\(\medspace = 2^{5} \)
$\operatorname{res}(\operatorname{Aut}(G))$$D_8:C_2$, of order \(32\)\(\medspace = 2^{5} \)
$\card{\operatorname{ker}(\operatorname{res})}$\(8\)\(\medspace = 2^{3} \)
$W$$\SD_{16}$, of order \(16\)\(\medspace = 2^{4} \)

Related subgroups

Centralizer:$C_8$
Normalizer:$D_8:C_8$
Complements:$C_8$ $C_8$
Minimal over-subgroups:$D_8:C_2$
Maximal under-subgroups:$C_8$$Q_8$

Other information

Möbius function$0$
Projective image$D_4:C_8$