Properties

Label 128.902.2.a1.b1
Order $ 2^{6} $
Index $ 2 $
Normal Yes

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Subgroup ($H$) information

Description:$\OD_{32}:C_2$
Order: \(64\)\(\medspace = 2^{6} \)
Index: \(2\)
Exponent: \(16\)\(\medspace = 2^{4} \)
Generators: $\left(\begin{array}{rr} 13 & 0 \\ 0 & 4 \end{array}\right), \left(\begin{array}{rr} 9 & 0 \\ 0 & 9 \end{array}\right), \left(\begin{array}{rr} 1 & 0 \\ 0 & 16 \end{array}\right), \left(\begin{array}{rr} 16 & 0 \\ 0 & 16 \end{array}\right), \left(\begin{array}{rr} 3 & 0 \\ 0 & 3 \end{array}\right), \left(\begin{array}{rr} 0 & 1 \\ 13 & 0 \end{array}\right)$ Copy content Toggle raw display
Nilpotency class: $2$
Derived length: $2$

The subgroup is normal, maximal, a semidirect factor, 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: $C_2$
Order: \(2\)
Exponent: \(2\)
Automorphism Group: $C_1$, of order $1$
Outer Automorphisms: $C_1$, of order $1$
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), a $p$-group, simple, 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_4^2.C_2^4$, of order \(256\)\(\medspace = 2^{8} \)
$\operatorname{Aut}(H)$ $C_2^4.D_6$, of order \(192\)\(\medspace = 2^{6} \cdot 3 \)
$\operatorname{res}(S)$$C_4^2:C_2^2$, of order \(64\)\(\medspace = 2^{6} \)
$\card{\operatorname{ker}(\operatorname{res})}$\(2\)
$W$$D_4$, of order \(8\)\(\medspace = 2^{3} \)

Related subgroups

Centralizer:$C_{16}$
Normalizer:$C_{16}.D_4$
Complements:$C_2$
Minimal over-subgroups:$C_{16}.D_4$
Maximal under-subgroups:$\OD_{16}:C_2$$C_2\times C_{16}$$\OD_{32}$$C_2\times C_{16}$$\OD_{32}$
Autjugate subgroups:128.902.2.a1.a1

Other information

Möbius function$-1$
Projective image$D_4$