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G = D7  order 14 = 2·7

Dihedral group

metacyclic, supersoluble, monomial, Z-group, 2-hyperelementary

Aliases: D7, C7⋊C2, sometimes denoted D14 or Dih7 or Dih14, SmallGroup(14,1)

Series: Derived ►Chief ►Lower central ►Upper central

C1 — C7 — D7
C1 — C7 — D7
C7 — D7
C1

Generators and relations for D7
 G = < a,b | a7=b2=1, bab=a-1 >

7C2

Character table of D7

 class 127A7B7C
 size 17222
ρ111111    trivial
ρ21-1111    linear of order 2
ρ320ζ76+ζ7ζ75+ζ72ζ74+ζ73    orthogonal faithful
ρ420ζ74+ζ73ζ76+ζ7ζ75+ζ72    orthogonal faithful
ρ520ζ75+ζ72ζ74+ζ73ζ76+ζ7    orthogonal faithful

Permutation representations of D7
►On 7 points: primitive - transitive group 7T2
Generators in S7
(1 2 3 4 5 6 7)
(1 7)(2 6)(3 5)
 
G:=sub<Sym(7)| (1,2,3,4,5,6,7), (1,7)(2,6)(3,5)>;
 
G:=Group( (1,2,3,4,5,6,7), (1,7)(2,6)(3,5) );
 
G=PermutationGroup([[(1,2,3,4,5,6,7)], [(1,7),(2,6),(3,5)]])
 
G:=TransitiveGroup(7,2);
 

►Regular action on 14 points - transitive group 14T2
Generators in S14
(1 2 3 4 5 6 7)(8 9 10 11 12 13 14)
(1 12)(2 11)(3 10)(4 9)(5 8)(6 14)(7 13)
 
G:=sub<Sym(14)| (1,2,3,4,5,6,7)(8,9,10,11,12,13,14), (1,12)(2,11)(3,10)(4,9)(5,8)(6,14)(7,13)>;
 
G:=Group( (1,2,3,4,5,6,7)(8,9,10,11,12,13,14), (1,12)(2,11)(3,10)(4,9)(5,8)(6,14)(7,13) );
 
G=PermutationGroup([[(1,2,3,4,5,6,7),(8,9,10,11,12,13,14)], [(1,12),(2,11),(3,10),(4,9),(5,8),(6,14),(7,13)]])
 
G:=TransitiveGroup(14,2);
 

D7 is a maximal subgroup of
 F7  C7⋊D7
 D7p: D21  D35  D49  D77  D91  D119  D133  D161 ...
D7 is a maximal quotient of
 Dic7  C7⋊D7
 D7p: D21  D35  D49  D77  D91  D119  D133  D161 ...

Polynomial with Galois group D7 over ℚ
actionf(x)Disc(f)
7T2x7-2x6-x5+x4+x3+x2-x-1-713
14T2x14+9x12+53x10+333x8+1251x6+731x4+5415x2+8591-2182·74·112·717

Matrix representation of D7 ►in GL2(𝔽13) generated by

118
512
,
120
81
G:=sub<GL(2,GF(13))| [11,5,8,12],[12,8,0,1] >;
 

D7 in GAP, Magma, Sage, TeX

D_7
 
% in TeX
 
G:=Group("D7");
 
// GroupNames label
 
G:=SmallGroup(14,1);
 
// by ID
 
G=gap.SmallGroup(14,1);
 
# by ID
 
G:=PCGroup([2,-2,-7,49]);
 
// Polycyclic
 
G:=Group<a,b|a^7=b^2=1,b*a*b=a^-1>;
 
// generators/relations
 

Export

Subgroup lattice of D7 in TeX
Character table of D7 in TeX

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