Small group number 24 of order 32
G is the group 32gp24
The Hall-Senior number of this group is 16.
G has 3 minimal generators, rank 3 and exponent 4.
The centre has rank 2.
The 7 maximal subgroups are:
Ab(4,2,2), Ab(4,4) (2x), 16gp3 (2x), 16gp4 (2x).
There is one conjugacy class of maximal elementary abelian
subgroups. Each maximal elementary abelian has rank 3.
This cohomology ring calculation is complete.
Ring structure
| Completion information
| Koszul information
| Restriction information
| Poincaré series
The cohomology ring has 6 generators:
- y1 in degree 1, a nilpotent element
- y2 in degree 1, a nilpotent element
- y3 in degree 1
- x in degree 2, a regular element
- w in degree 3
- v in degree 4, a regular element
There are 5 minimal relations:
- y1.y3 =
y22
- y12 =
0
- y22.y3 =
0
- y1.w =
y22.x
- w2 =
y34.x
+ y32.x2
A minimal Gröbner basis for the relations ideal
consists of this minimal generating set, together with the
following redundant relations:
- y1.y22 =
0
- y24 =
0
- y22.w =
0
Essential ideal:
There is one minimal generator:
Nilradical:
There are 2 minimal generators:
This cohomology ring was obtained from a calculation
out to degree 12. The cohomology ring approximation
is stable from degree 6 onwards, and
Carlson's tests detect stability from degree 8
onwards.
This cohomology ring has dimension 3 and depth 2.
Here is a homogeneous system of parameters:
- h1 =
x
in degree 2
- h2 =
v
in degree 4
- h3 =
y32
in degree 2
The first
2 terms h1, h2 form
a regular sequence of maximum length.
The remaining
term h3 is
annihilated by the class
y1.
The first
2 terms h1, h2 form
a complete Duflot regular sequence.
That is, their restrictions to the greatest central elementary abelian
subgroup form a regular sequence of maximal length.
The ideal of essential classes is
free of rank 1 as a module over the polynomial algebra
on h1, h2.
These free generators are:
The essential ideal squares to zero.
A basis for R/(h1, h2, h3) is as follows.
Carlson's Koszul condition stipulates that this must
be confined to degrees less than 8.
-
1
in degree 0
-
y3
in degree 1
-
y2
in degree 1
-
y1
in degree 1
-
y2.y3
in degree 2
-
y22
in degree 2
-
y1.y2
in degree 2
-
w
in degree 3
-
y23
in degree 3
-
y3.w
in degree 4
-
y2.w
in degree 4
-
y2.y3.w
in degree 5
A basis for AnnR/(h1, h2)(h3) is as follows.
Carlson's Koszul condition stipulates that this must
be confined to degrees less than 6.
-
y1
in degree 1
-
y22
in degree 2
-
y1.y2
in degree 2
-
y23
in degree 3
Restriction to maximal subgroup number 1, which is 16gp10
- y1 restricts to
0
- y2 restricts to
y1
- y3 restricts to
y2
- x restricts to
y32
- w restricts to
y2.y32
+ y22.y3
- v restricts to
x2
+ y22.x
Restriction to maximal subgroup number 2, which is 16gp2
- y1 restricts to
y2
- y2 restricts to
y1
- y3 restricts to
0
- x restricts to
x2
- w restricts to
y2.x1
- v restricts to
x12
Restriction to maximal subgroup number 3, which is 16gp2
- y1 restricts to
y2
- y2 restricts to
y1
- y3 restricts to
y2
- x restricts to
x2
- w restricts to
y2.x1
- v restricts to
x22
+ x12
Restriction to maximal subgroup number 4, which is 16gp3
- y1 restricts to
y1
- y2 restricts to
0
- y3 restricts to
y2
- x restricts to
x2
- w restricts to
y2.x1
+ y2.x2
+ y1.x3
- v restricts to
x32
Restriction to maximal subgroup number 5, which is 16gp3
- y1 restricts to
y1
- y2 restricts to
y1
- y3 restricts to
y2
- x restricts to
y22
+ x2
- w restricts to
y2.x1
+ y2.x2
+ y1.x3
+ y1.x2
- v restricts to
y22.x2
+ x32
+ x22
Restriction to maximal subgroup number 6, which is 16gp4
- y1 restricts to
y1
- y2 restricts to
y2
- y3 restricts to
y2
- x restricts to
x1
- w restricts to
y2.x1
+ y1.x2
- v restricts to
x22
Restriction to maximal subgroup number 7, which is 16gp4
- y1 restricts to
y1
- y2 restricts to
y2
- y3 restricts to
y2
+ y1
- x restricts to
x1
- w restricts to
y2.x1
+ y1.x2
- v restricts to
x22
+ x12
Restriction to maximal elementary abelian number 1, which is V8
- y1 restricts to
0
- y2 restricts to
0
- y3 restricts to
y2
- x restricts to
y32
+ y12
- w restricts to
y2.y32
+ y22.y3
+ y1.y22
+ y12.y2
- v restricts to
y34
+ y22.y32
Restriction to the greatest central elementary abelian, which is V4
- y1 restricts to
0
- y2 restricts to
0
- y3 restricts to
0
- x restricts to
y22
- w restricts to
0
- v restricts to
y14
(1 + 3t + 3t2
+ t3) /
(1 - t2)2 (1 - t4)
Back to the groups of order 32