Properties

Label 128.902.4.a1.b1
Order $ 2^{5} $
Index $ 2^{2} $
Normal Yes

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Subgroup ($H$) information

Description:$C_4\wr C_2$
Order: \(32\)\(\medspace = 2^{5} \)
Index: \(4\)\(\medspace = 2^{2} \)
Exponent: \(8\)\(\medspace = 2^{3} \)
Generators: $\left(\begin{array}{rr} 1 & 0 \\ 0 & 13 \end{array}\right), \left(\begin{array}{rr} 13 & 0 \\ 0 & 4 \end{array}\right), \left(\begin{array}{rr} 1 & 0 \\ 0 & 16 \end{array}\right), \left(\begin{array}{rr} 16 & 0 \\ 0 & 16 \end{array}\right), \left(\begin{array}{rr} 0 & 9 \\ 9 & 0 \end{array}\right)$ Copy content Toggle raw display
Nilpotency class: $3$
Derived length: $2$

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

Ambient group ($G$) information

Description: $C_{16}.D_4$
Order: \(128\)\(\medspace = 2^{7} \)
Exponent: \(16\)\(\medspace = 2^{4} \)
Nilpotency class:$3$
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: $C_4$
Order: \(4\)\(\medspace = 2^{2} \)
Exponent: \(4\)\(\medspace = 2^{2} \)
Automorphism Group: $C_2$, of order \(2\)
Outer Automorphisms: $C_2$, of order \(2\)
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

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_4^2.C_2^4$, of order \(256\)\(\medspace = 2^{8} \)
$\operatorname{Aut}(H)$ $C_2^2\times D_4$, of order \(32\)\(\medspace = 2^{5} \)
$\operatorname{res}(S)$$C_2^2\times D_4$, of order \(32\)\(\medspace = 2^{5} \)
$\card{\operatorname{ker}(\operatorname{res})}$\(4\)\(\medspace = 2^{2} \)
$W$$D_4$, of order \(8\)\(\medspace = 2^{3} \)

Related subgroups

Centralizer:$C_{16}$
Normalizer:$C_{16}.D_4$
Minimal over-subgroups:$D_8:C_4$
Maximal under-subgroups:$D_4:C_2$$C_4^2$$\OD_{16}$
Autjugate subgroups:128.902.4.a1.a1

Other information

Möbius function$0$
Projective image$C_4\times D_4$