Properties

Label 840.7.20.a1.a1
Order $ 2 \cdot 3 \cdot 7 $
Index $ 2^{2} \cdot 5 $
Normal Yes

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Subgroup ($H$) information

Description:$C_{42}$
Order: \(42\)\(\medspace = 2 \cdot 3 \cdot 7 \)
Index: \(20\)\(\medspace = 2^{2} \cdot 5 \)
Exponent: \(42\)\(\medspace = 2 \cdot 3 \cdot 7 \)
Generators: $a^{4}, b^{15}, b^{70}$ Copy content Toggle raw display
Nilpotency class: $1$
Derived length: $1$

The subgroup is characteristic (hence normal) and cyclic (hence abelian, nilpotent, solvable, supersolvable, monomial, elementary ($p = 2,3,7$), hyperelementary, metacyclic, metabelian, a Z-group, and an A-group).

Ambient group ($G$) information

Description: $C_{105}:C_8$
Order: \(840\)\(\medspace = 2^{3} \cdot 3 \cdot 5 \cdot 7 \)
Exponent: \(840\)\(\medspace = 2^{3} \cdot 3 \cdot 5 \cdot 7 \)
Derived length:$2$

The ambient group is nonabelian, a Z-group (hence solvable, supersolvable, monomial, metacyclic, metabelian, and an A-group), and hyperelementary for $p = 2$.

Quotient group ($Q$) structure

Description: $C_5:C_4$
Order: \(20\)\(\medspace = 2^{2} \cdot 5 \)
Exponent: \(20\)\(\medspace = 2^{2} \cdot 5 \)
Automorphism Group: $C_2\times F_5$, of order \(40\)\(\medspace = 2^{3} \cdot 5 \)
Outer Automorphisms: $C_2^2$, of order \(4\)\(\medspace = 2^{2} \)
Nilpotency class: $-1$
Derived length: $2$

The quotient is nonabelian, a Z-group (hence solvable, supersolvable, monomial, metacyclic, metabelian, and an A-group), and hyperelementary for $p = 2$.

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_2^3\times F_5\times F_7$
$\operatorname{Aut}(H)$ $C_2\times C_6$, of order \(12\)\(\medspace = 2^{2} \cdot 3 \)
$\operatorname{res}(\operatorname{Aut}(G))$$C_2\times C_6$, of order \(12\)\(\medspace = 2^{2} \cdot 3 \)
$\card{\operatorname{ker}(\operatorname{res})}$\(560\)\(\medspace = 2^{4} \cdot 5 \cdot 7 \)
$W$$C_2$, of order \(2\)

Related subgroups

Centralizer:$C_{420}$
Normalizer:$C_{105}:C_8$
Minimal over-subgroups:$C_{210}$$C_{84}$
Maximal under-subgroups:$C_{21}$$C_{14}$$C_6$

Other information

Möbius function$0$
Projective image$C_{35}:C_4$