Properties

Label 8.4.2.a1.a1
Order $ 2^{2} $
Index $ 2 $
Normal Yes

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Subgroup ($H$) information

Description:$C_4$
Order: \(4\)\(\medspace = 2^{2} \)
Index: \(2\)
Exponent: \(4\)\(\medspace = 2^{2} \)
Generators: $b$ Copy content Toggle raw display
Nilpotency class: $1$
Derived length: $1$

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

Ambient group ($G$) information

Description: $Q_8$
Order: \(8\)\(\medspace = 2^{3} \)
Exponent: \(4\)\(\medspace = 2^{2} \)
Nilpotency class:$2$
Derived length:$2$

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

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)$$S_4$, of order \(24\)\(\medspace = 2^{3} \cdot 3 \)
$\operatorname{Aut}(H)$ $C_2$, of order \(2\)
$\operatorname{res}(S)$$C_2$, of order \(2\)
$\card{\operatorname{ker}(\operatorname{res})}$\(4\)\(\medspace = 2^{2} \)
$W$$C_2$, of order \(2\)

Related subgroups

Centralizer:$C_4$
Normalizer:$Q_8$
Minimal over-subgroups:$Q_8$
Maximal under-subgroups:$C_2$
Autjugate subgroups:8.4.2.a1.b18.4.2.a1.c1

Other information

Möbius function$-1$
Projective image$C_2^2$