Properties

Label 84.7.42.a1.a1
Order $ 2 $
Index $ 2 \cdot 3 \cdot 7 $
Normal Yes

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Subgroup ($H$) information

Description:$C_2$
Order: \(2\)
Index: \(42\)\(\medspace = 2 \cdot 3 \cdot 7 \)
Exponent: \(2\)
Generators: $b^{7}$ Copy content Toggle raw display
Nilpotency class: $1$
Derived length: $1$

The subgroup is the center (hence characteristic, normal, abelian, central, nilpotent, solvable, supersolvable, monomial, metabelian, and an A-group), a direct factor, cyclic (hence elementary, hyperelementary, metacyclic, and a Z-group), a $p$-group, simple, and rational.

Ambient group ($G$) information

Description: $C_2\times F_7$
Order: \(84\)\(\medspace = 2^{2} \cdot 3 \cdot 7 \)
Exponent: \(42\)\(\medspace = 2 \cdot 3 \cdot 7 \)
Derived length:$2$

The ambient group is nonabelian, metacyclic (hence solvable, supersolvable, monomial, and metabelian), and an A-group.

Quotient group ($Q$) structure

Description: $F_7$
Order: \(42\)\(\medspace = 2 \cdot 3 \cdot 7 \)
Exponent: \(42\)\(\medspace = 2 \cdot 3 \cdot 7 \)
Automorphism Group: $F_7$, of order \(42\)\(\medspace = 2 \cdot 3 \cdot 7 \)
Outer Automorphisms: $C_1$, of order $1$
Nilpotency class: $-1$
Derived length: $2$

The quotient is nonabelian and a Z-group (hence solvable, supersolvable, monomial, metacyclic, metabelian, and an A-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_2\times F_7$, of order \(84\)\(\medspace = 2^{2} \cdot 3 \cdot 7 \)
$\operatorname{Aut}(H)$ $C_1$, of order $1$
$\operatorname{res}(\operatorname{Aut}(G))$$C_1$, of order $1$
$\card{\operatorname{ker}(\operatorname{res})}$\(84\)\(\medspace = 2^{2} \cdot 3 \cdot 7 \)
$W$$C_1$, of order $1$

Related subgroups

Centralizer:$C_2\times F_7$
Normalizer:$C_2\times F_7$
Complements:$F_7$ $F_7$
Minimal over-subgroups:$C_{14}$$C_6$$C_2^2$
Maximal under-subgroups:$C_1$

Other information

Möbius function$-7$
Projective image$F_7$