Small group number 1753 of order 128
G is the group 128gp1753
G has 4 minimal generators, rank 4 and exponent 8.
The centre has rank 1.
There are 9 conjugacy classes of maximal
elementary abelian subgroups. Their ranks are:
3, 3, 3, 3, 3, 3, 3, 3, 4.
This cohomology ring calculation is complete.
Ring structure
| Completion information
| Koszul information
| Restriction information
| Poincaré series
The cohomology ring has 9 generators:
- y1 in degree 1
- y2 in degree 1
- y3 in degree 1
- y4 in degree 1
- x1 in degree 2
- x2 in degree 2
- w in degree 3
- u in degree 5
- r in degree 8, a regular element
There are 14 minimal relations:
- y2.y4 =
0
- y1.y4 =
0
- y4.x2 =
0
- y2.y32 =
y1.x1
+ y1.y32
- x22 =
y22.x2
+ y1.y2.x2
+ y1.y2.x1
+ y12.y32
- x1.x2 =
y2.w
+ y1.w
+ y12.x1
- y32.x2 =
y1.w
+ y12.y32
- x2.w =
y22.w
+ y1.y34
+ y1.y2.w
+ y12.w
+ y13.y32
- y1.x12 =
y1.y32.x1
+ y12.y2.x1
- w2 =
y4.u
+ y4.x1.w
+ y32.x12
+ y32.y42.x1
+ y33.y4.x1
+ y34.x1
+ y35.y4
+ y36
+ y2.x1.w
+ y12.y34
+ y13.y2.x1
- y2.u =
y2.y3.x12
+ y22.y3.w
+ y23.w
+ y1.x1.w
+ y1.y32.w
+ y1.y2.y3.w
+ y1.y22.w
+ y1.y22.y3.x1
+ y1.y23.x1
+ y12.y32.x1
+ y12.y34
+ y12.y2.w
+ y12.y2.y3.x1
+ y12.y22.x1
+ y13.y3.x1
+ y13.y33
+ y14.x1
+ y14.y32
- y1.u =
y1.x1.w
+ y1.y32.w
+ y1.y2.y3.w
+ y1.y22.w
+ y12.y3.w
+ y12.y34
+ y12.y22.x1
+ y13.y33
+ y13.y2.x1
+ y14.y32
- x2.u =
y2.y3.x1.w
+ y23.y3.w
+ y24.w
+ y1.y34.x1
+ y1.y36
+ y1.y22.y3.w
+ y1.y23.w
+ y12.x1.w
+ y12.y33.x1
+ y12.y2.y3.w
+ y13.y34
+ y13.y2.w
+ y13.y22.x1
+ y14.w
+ y14.y3.x1
+ y14.y33
+ y14.y2.x1
+ y15.x1
- u2 =
y45.u
+ y47.w
+ y3.y42.x1.u
+ y3.y42.x12.w
+ y3.y44.x1.w
+ y3.y45.x12
+ y3.y46.w
+ y3.y47.x1
+ y32.x14
+ y32.y4.x1.u
+ y32.y42.x13
+ y32.y43.u
+ y32.y44.x12
+ y32.y46.x1
+ y33.y4.x13
+ y33.y43.x12
+ y34.x13
+ y34.y4.u
+ y35.y4.x12
+ y35.y42.w
+ y35.y43.x1
+ y35.y45
+ y37.y4.x1
+ y37.y43
+ y38.x1
+ y38.y42
+ y39.y4
+ y310
+ y25.x1.w
+ y13.y25.x1
+ y14.y24.x1
+ y15.y22.w
+ y16.y32.x1
+ y16.y2.w
+ y16.y22.x1
+ y17.y2.x1
+ y42.r
A minimal Gröbner basis for the relations ideal
consists of this minimal generating set, together with the
following redundant relation:
- y1.y2.x1.w =
y12.y22.w
+ y13.y2.w
This cohomology ring was obtained from a calculation
out to degree 18. The cohomology ring approximation
is stable from degree 10 onwards, and
Benson's tests detect stability from degree 11
onwards.
This cohomology ring has dimension 4 and depth 3.
Here is a homogeneous system of parameters:
- h1 =
r
in degree 8
- h2 =
x1
+ y32
+ y12
in degree 2
- h3 =
x1
+ y22
in degree 2
- h4 =
y42
in degree 2
The first
3 terms h1, h2, h3 form
a regular sequence of maximum length.
The first
term h1 forms
a complete Duflot regular sequence.
That is, its restriction to the greatest central elementary abelian
subgroup forms a regular sequence of maximal length.
Data for Benson's test:
-
Raw filter degree type:
-1, -1, -1, 8, 10.
-
Filter degree type:
-1, -2, -3, -4, -4.
-
α = 0
-
The system of parameters is very strongly quasi-regular.
-
The regularity conjecture is satisfied.
A basis for R/(h1, h2, h3, h4) is as follows.
-
1
in degree 0
-
y4
in degree 1
-
y3
in degree 1
-
y2
in degree 1
-
y1
in degree 1
-
x2
in degree 2
-
y3.y4
in degree 2
-
y2.y3
in degree 2
-
y22
in degree 2
-
y1.y3
in degree 2
-
y1.y2
in degree 2
-
y12
in degree 2
-
w
in degree 3
-
y3.x2
in degree 3
-
y2.x2
in degree 3
-
y22.y3
in degree 3
-
y1.x2
in degree 3
-
y1.y2.y3
in degree 3
-
y1.y22
in degree 3
-
y12.y3
in degree 3
-
y12.y2
in degree 3
-
y13
in degree 3
-
y4.w
in degree 4
-
y3.w
in degree 4
-
y2.y3.x2
in degree 4
-
y1.w
in degree 4
-
y1.y3.x2
in degree 4
-
y1.y2.x2
in degree 4
-
y1.y22.y3
in degree 4
-
y12.x2
in degree 4
-
y12.y2.y3
in degree 4
-
y12.y22
in degree 4
-
y13.y3
in degree 4
-
y13.y2
in degree 4
-
y14
in degree 4
-
u
in degree 5
-
y3.y4.w
in degree 5
-
y1.y3.w
in degree 5
-
y1.y2.y3.x2
in degree 5
-
y12.w
in degree 5
-
y12.y3.x2
in degree 5
-
y12.y2.x2
in degree 5
-
y12.y22.y3
in degree 5
-
y13.x2
in degree 5
-
y13.y2.y3
in degree 5
-
y14.y3
in degree 5
-
y14.y2
in degree 5
-
y15
in degree 5
-
y4.u
in degree 6
-
y3.u
in degree 6
-
y12.y3.w
in degree 6
-
y12.y2.y3.x2
in degree 6
-
y13.w
in degree 6
-
y13.y3.x2
in degree 6
-
y13.y2.x2
in degree 6
-
y14.x2
in degree 6
-
y14.y2.y3
in degree 6
-
y15.y3
in degree 6
-
y16
in degree 6
-
y3.y4.u
in degree 7
-
y13.y3.w
in degree 7
-
y13.y2.y3.x2
in degree 7
-
y14.y3.x2
in degree 7
-
y14.y2.x2
in degree 7
-
y15.x2
in degree 7
-
y16.y3
in degree 7
-
w.u
in degree 8
-
y14.y2.y3.x2
in degree 8
-
y15.y3.x2
in degree 8
-
y4.w.u
in degree 9
-
y3.w.u
in degree 9
-
y3.y4.w.u
in degree 10
A basis for AnnR/(h1, h2, h3)(h4) is as follows.
-
y2
in degree 1
-
y1
in degree 1
-
x2
in degree 2
-
y2.y3
in degree 2
-
y22
in degree 2
-
y1.y3
in degree 2
-
y1.y2
in degree 2
-
y12
in degree 2
-
y3.x2
in degree 3
-
y2.x2
in degree 3
-
y22.y3
in degree 3
-
y1.x2
in degree 3
-
y1.y2.y3
in degree 3
-
y1.y22
in degree 3
-
y12.y3
in degree 3
-
y12.y2
in degree 3
-
y13
in degree 3
-
y2.y3.x2
in degree 4
-
y1.w
in degree 4
-
y1.y3.x2
in degree 4
-
y1.y2.x2
in degree 4
-
y1.y22.y3
in degree 4
-
y12.x2
in degree 4
-
y12.y2.y3
in degree 4
-
y12.y22
in degree 4
-
y13.y3
in degree 4
-
y13.y2
in degree 4
-
y14
in degree 4
-
y1.y3.w
in degree 5
-
y1.y2.y3.x2
in degree 5
-
y12.w
in degree 5
-
y12.y3.x2
in degree 5
-
y12.y2.x2
in degree 5
-
y12.y22.y3
in degree 5
-
y13.x2
in degree 5
-
y13.y2.y3
in degree 5
-
y14.y3
in degree 5
-
y14.y2
in degree 5
-
y15
in degree 5
-
y12.y3.w
in degree 6
-
y12.y2.y3.x2
in degree 6
-
y13.w
in degree 6
-
y13.y3.x2
in degree 6
-
y13.y2.x2
in degree 6
-
y14.x2
in degree 6
-
y14.y2.y3
in degree 6
-
y15.y3
in degree 6
-
y16
in degree 6
-
y13.y3.w
in degree 7
-
y13.y2.y3.x2
in degree 7
-
y14.y3.x2
in degree 7
-
y14.y2.x2
in degree 7
-
y15.x2
in degree 7
-
y16.y3
in degree 7
-
y14.y2.y3.x2
in degree 8
-
y15.y3.x2
in degree 8