GROUP OF ORDER 32 #30

GROUP #30

The MAGMA library number for G is 13

GrpPC : G of order 32 = 2^5 PC-Relations: G.1^2 = G.3 * G.5, G.2^2 = G.3, G.4^2 = G.5, G.2^G.1 = G.2 * G.4, G.4^G.1 = G.4 * G.5, G.4^G.2 = G.4 * G.5

The center of G is abelian of type [ 2, 2 ] .
The orders of the terms of the lower central series are [ 32, 4, 2, 1 ] .
The orders of the terms of the upper central series are [ 1, 4, 8, 32 ] .
The order of the Frattini subgroup is 8.
The exponent of G is 8.
G has a unique maximal elementary abelian subgroup which is central in G and has order 4.

The cohomology ring of G is the quotient of a polynomial ring in the variables
[ z, y, x, w ] in degrees [ 1, 1, 2, 2 ] , by the ideal generated by the relations
z2 + y2 ,
zy .

The Hilbert series for the cohomology ring is
1 / t2 -2t+ 1.
Its denominator factors as ( t-1 )2 .

The Krull dimension of the cohomology ring is 2.
The cohomology ring is Cohen-Macaulay and the longest regular sequence consists of the generators
x , w .

Restriction to the Maximal Elementary Abelian Subgroup

Generated by [ G.3, G.3 * G.5 ] The cohomology ring of E is a polynomial ring in the variables z , y .

The images of the generators of the cohomology of G restricted to E are
0 ,
0 ,
z2 ,
z2 + y2
in the cohomology of E.

The kernel of the restriction to E (Minimal Prime) of the cohomology of G is generated by
z ,
y .

This ideal is also the nilradical of the cohomology of G.

It is nilpotent of degree 3.

Restrictions to Maximal Subgroups

Maximal Subgroup H #1 Generated by [ G.3, G.1 * G.2, G.4, G.5 ] .

The group H is abelian of type [ 8, 2 ]

The cohomology ring of H is a the quotient of a polynomial ring in the variables
[ z, y, x ] , in degrees [ 1, 1, 2 ] , by the ideal of relations
z2 .

The images of the generators of the cohomology of G restricted to H are
z ,
z ,
zy + x ,
y2
in the cohomology of H.

The kernel of the restriction to H of the cohomology of G is generated by
z + y .

Maximal Subgroup H #2 Generated by [ G.3, G.4, G.1, G.5 ] .

The Group H is Isomorphic to the Group of Order 16 Number10 GrpPC of order 16 = 2^4 PC-Relations: $.1^2 = $.3, $.2^2 = $.3, $.2^$.1 = $.2 * $.4 Generated by [ G.1 * G.4 * G.5, G.1 ] .

The images of the generators of the cohomology of G restricted to H are
z + y ,
0 ,
z2 + x + w ,
w
in the cohomology of H.

The kernel of the restriction to H of the cohomology of G is generated by
y .

Maximal Subgroup H #3 Generated by [ G.3, G.2, G.4, G.5 ] .

The Group H is Isomorphic to the Group of Order 16 Number10 GrpPC of order 16 = 2^4 PC-Relations: $.1^2 = $.3, $.2^2 = $.3, $.2^$.1 = $.2 * $.4 Generated by [ G.2 * G.4 * G.5, G.2 ] .

The images of the generators of the cohomology of G restricted to H are
0 ,
z + y ,
z2 + x ,
w
in the cohomology of H.

The kernel of the restriction to H of the cohomology of G is generated by
z .

The essential cohomology of G is generated as an ideal by
y2 .

It is nilpotent of degree 2.
The annihilator of the Essential Cohomology has dimension 2 .
The essential cohomology is a free module over the polynomial subring Q of the cohomology ring of G generated by x , w .
The essential cohomology is generated as a module over Q by the elements
[] [ y2 ]

Inflations from Maximal Quotient Groups

Maximal Quotient Group Q #1

The kernel of the quotient is generated by G.5 .

The Group Q is Isomorphic to the Group of Order 16 Number10 GrpPC of order 16 = 2^4 PC-Relations: $.1^2 = $.3, $.2^2 = $.3, $.2^$.1 = $.2 * $.4 .

The generators of G have images [ pcy.2, pcy.1 ] in the quotient group.

The images of the generators of the cohomology of Q inflated to G are
z ,
y ,
z2 ,
w
in the cohomology of G.

The kernel of the inflation to G of the cohomology of Q is generated by
y2 + x .

Maximal Quotient Group Q #2

The kernel of the quotient is generated by G.3 .

The Group Q is Isomorphic to the Group of Order 16 Number13 GrpPC of order 16 = 2^4 PC-Relations: $.1^2 = $.3 * $.4, $.3^2 = $.4, $.2^$.1 = $.2 * $.3, $.3^$.2 = $.3 * $.4

of type Semidihedral(16) .

The generators of G have images [ pcy.2, pcy.1 * pcy.2 ] in the quotient group.

The images of the generators of the cohomology of Q inflated to G are
z ,
z + y ,
yx ,
z2x + y2w + x2
in the cohomology of G.

The kernel of the inflation to G of the cohomology of Q is generated by
y2 .

Maximal Quotient Group Q #3

The kernel of the quotient is generated by G.3 * G.5 .

The Group Q is Isomorphic to the Group of Order 16 Number13 GrpPC of order 16 = 2^4 PC-Relations: $.1^2 = $.3 * $.4, $.3^2 = $.4, $.2^$.1 = $.2 * $.3, $.3^$.2 = $.3 * $.4

of type Semidihedral(16) .

The generators of G have images [ pcy.1 * pcy.2, pcy.2 ] in the quotient group.

The images of the generators of the cohomology of Q inflated to G are
y ,
z + y ,
zx + zw ,
z2x + x2 + w2
in the cohomology of G.

The kernel of the inflation to G of the cohomology of Q is generated by
y2 .

Action of Automorphisms

The groups of outer automorphisms of G has order 16, and is generated by 4 elements.

Automorphism #1

The order of the class of the automorphism in the outer automorphism group is 2. The images of the generators of G are

    G.1 * G.5
    G.2
    G.3
    G.4
    G.5 .

The images of the generators of the cohomology of G under the map induced by the automorphism are
z ,
y ,
x ,
w .

Automorphism #2

The order of the class of the automorphism in the outer automorphism group is 2. The images of the generators of G are

    G.1 * G.3
    G.2 * G.3
    G.3
    G.4
    G.5 .

The images of the generators of the cohomology of G under the map induced by the automorphism are
z ,
y ,
z2 + x ,
w .

Automorphism #3

The order of the class of the automorphism in the outer automorphism group is 2. The images of the generators of G are

    G.1 * G.3
    G.2
    G.3
    G.4
    G.5 .

The images of the generators of the cohomology of G under the map induced by the automorphism are
z ,
y ,
z2 + x ,
z2 + w .

Automorphism #4

The order of the class of the automorphism in the outer automorphism group is 2. The images of the generators of G are

    G.2 * G.5
    G.1 * G.4 * G.5
    G.3 * G.5
    G.4
    G.5 .

The images of the generators of the cohomology of G under the map induced by the automorphism are
y ,
z ,
x + w ,
w .

CHECKS

paramflag = true
qregflagflag = true
cmflag = true
essflag = true
centflag = true

THE COMPUTATION IS COMPLETE