Properties

Label 100.10.4.a1.a1
Order $ 5^{2} $
Index $ 2^{2} $
Normal Yes

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Subgroup ($H$) information

Description:$C_5^2$
Order: \(25\)\(\medspace = 5^{2} \)
Index: \(4\)\(\medspace = 2^{2} \)
Exponent: \(5\)
Generators: $b, c$ Copy content Toggle raw display
Nilpotency class: $1$
Derived length: $1$

The subgroup is the commutator subgroup (hence characteristic and normal), the Fitting subgroup (hence nilpotent, solvable, supersolvable, and monomial), the socle, a semidirect factor, abelian (hence metabelian and an A-group), a $5$-Sylow subgroup (hence a Hall subgroup), a $p$-group (hence elementary and hyperelementary), and metacyclic.

Ambient group ($G$) information

Description: $C_5:F_5$
Order: \(100\)\(\medspace = 2^{2} \cdot 5^{2} \)
Exponent: \(20\)\(\medspace = 2^{2} \cdot 5 \)
Derived length:$2$

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

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

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)$$F_5^2$, of order \(400\)\(\medspace = 2^{4} \cdot 5^{2} \)
$\operatorname{Aut}(H)$ $\GL(2,5)$, of order \(480\)\(\medspace = 2^{5} \cdot 3 \cdot 5 \)
$\operatorname{res}(\operatorname{Aut}(G))$$C_4^2$, of order \(16\)\(\medspace = 2^{4} \)
$\card{\operatorname{ker}(\operatorname{res})}$\(25\)\(\medspace = 5^{2} \)
$W$$C_4$, of order \(4\)\(\medspace = 2^{2} \)

Related subgroups

Centralizer:$C_5^2$
Normalizer:$C_5:F_5$
Complements:$C_4$
Minimal over-subgroups:$C_5\times D_5$
Maximal under-subgroups:$C_5$$C_5$$C_5$

Other information

Möbius function$0$
Projective image$C_5:F_5$