Properties

Label 21T4
Degree $21$
Order $42$
Cyclic no
Abelian no
Solvable yes
Primitive no
$p$-group no
Group: $F_7$

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Show commands: Magma

magma: G := TransitiveGroup(21, 4);
 

Group action invariants

Degree $n$:  $21$
magma: t, n := TransitiveGroupIdentification(G); n;
 
Transitive number $t$:  $4$
magma: t, n := TransitiveGroupIdentification(G); t;
 
Group:  $F_7$
Parity:  $-1$
magma: IsEven(G);
 
Primitive:  no
magma: IsPrimitive(G);
 
magma: NilpotencyClass(G);
 
$\card{\Aut(F/K)}$:  $3$
magma: Order(Centralizer(SymmetricGroup(n), G));
 
Generators:  (1,9,5,18,10,14)(2,8,6,16,12,13)(3,7,4,17,11,15)(19,21,20), (1,4,8,12,15,18,19)(2,5,7,11,14,16,20)(3,6,9,10,13,17,21)
magma: Generators(G);
 

Low degree resolvents

|G/N|Galois groups for stem field(s)
$2$:  $C_2$
$3$:  $C_3$
$6$:  $C_6$

Resolvents shown for degrees $\leq 47$

Subfields

Degree 3: $C_3$

Degree 7: $F_7$

Low degree siblings

7T4, 14T4, 42T4

Siblings are shown with degree $\leq 47$

A number field with this Galois group has no arithmetically equivalent fields.

Conjugacy classes

LabelCycle TypeSizeOrderRepresentative
$ 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 $ $1$ $1$ $()$
$ 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1 $ $7$ $2$ $( 4,19)( 5,20)( 6,21)( 7,16)( 8,18)( 9,17)(10,13)(11,14)(12,15)$
$ 3, 3, 3, 3, 3, 3, 3 $ $7$ $3$ $( 1, 2, 3)( 4, 7,13)( 5, 9,15)( 6, 8,14)(10,19,16)(11,21,18)(12,20,17)$
$ 6, 6, 6, 3 $ $7$ $6$ $( 1, 2, 3)( 4,16,13,19, 7,10)( 5,17,15,20, 9,12)( 6,18,14,21, 8,11)$
$ 6, 6, 6, 3 $ $7$ $6$ $( 1, 3, 2)( 4,10, 7,19,13,16)( 5,12, 9,20,15,17)( 6,11, 8,21,14,18)$
$ 3, 3, 3, 3, 3, 3, 3 $ $7$ $3$ $( 1, 3, 2)( 4,13, 7)( 5,15, 9)( 6,14, 8)(10,16,19)(11,18,21)(12,17,20)$
$ 7, 7, 7 $ $6$ $7$ $( 1, 4, 8,12,15,18,19)( 2, 5, 7,11,14,16,20)( 3, 6, 9,10,13,17,21)$

magma: ConjugacyClasses(G);
 

Group invariants

Order:  $42=2 \cdot 3 \cdot 7$
magma: Order(G);
 
Cyclic:  no
magma: IsCyclic(G);
 
Abelian:  no
magma: IsAbelian(G);
 
Solvable:  yes
magma: IsSolvable(G);
 
Nilpotency class:   not nilpotent
Label:  42.1
magma: IdentifyGroup(G);
 
Character table:

1A 2A 3A1 3A-1 6A1 6A-1 7A
Size 1 7 7 7 7 7 6
2 P 1A 1A 3A-1 3A1 3A1 3A-1 7A
3 P 1A 2A 1A 1A 2A 2A 7A
7 P 1A 2A 3A1 3A-1 6A1 6A-1 1A
Type
42.1.1a R 1 1 1 1 1 1 1
42.1.1b R 1 1 1 1 1 1 1
42.1.1c1 C 1 1 ζ31 ζ3 ζ3 ζ31 1
42.1.1c2 C 1 1 ζ3 ζ31 ζ31 ζ3 1
42.1.1d1 C 1 1 ζ31 ζ3 ζ3 ζ31 1
42.1.1d2 C 1 1 ζ3 ζ31 ζ31 ζ3 1
42.1.6a R 6 0 0 0 0 0 1

magma: CharacterTable(G);