Small group number 1615 of order 128
G is the group 128gp1615
G has 4 minimal generators, rank 4 and exponent 4.
The centre has rank 1.
There are 6 conjugacy classes of maximal
elementary abelian subgroups. Their ranks are:
4, 4, 4, 4, 4, 4.
This cohomology ring calculation is complete.
Ring structure
| Completion information
| Koszul information
| Restriction information
| Poincaré series
The cohomology ring has 11 generators:
- y1 in degree 1, a nilpotent element
- y2 in degree 1
- y3 in degree 1
- y4 in degree 1
- x1 in degree 2
- x2 in degree 2
- w in degree 3
- u1 in degree 5
- u2 in degree 5
- t in degree 6
- r in degree 8, a regular element
There are 27 minimal relations:
- y1.y4 =
0
- y12 =
0
- y4.x2 =
y2.y3.y4
+ y2.y32
+ y22.y3
+ y1.x1
- y1.y2.y3 =
0
- y4.w =
y3.y4.x1
+ y2.y3.x1
+ y1.y3.x1
+ y1.y2.x1
- y2.y3.x2 =
y2.y32.y4
+ y2.y33
+ y22.y3.y4
+ y22.y32
+ y23.y3
+ y1.w
+ y1.y2.x1
- y2.y3.y42 =
y2.y32.y4
+ y22.y3.y4
+ y22.y32
- y2.y3.w =
y2.y3.y4.x1
+ y22.y3.x1
+ y1.y3.w
+ y1.y2.w
+ y1.y22.x1
- y1.x1.x2 =
y1.x12
+ y1.y3.w
+ y1.y2.w
+ y1.y22.x1
- w2 =
x1.x22
+ x12.x2
+ y32.x1.x2
+ y32.x12
+ y22.x1.x2
+ y22.y32.x1
+ y1.x2.w
+ y1.x1.w
+ y1.y32.w
- y4.u2 =
y32.y42.x1
+ y2.y32.y4.x1
+ y2.y33.x1
+ y22.y3.y4.x1
+ y22.y32.x1
+ y22.y33.y4
+ y22.y34
+ y23.y3.x1
+ y23.y32.y4
+ y23.y33
+ y24.y32
+ y1.y3.x12
+ y1.y2.x12
- y1.u2 =
y1.x2.w
+ y1.x1.w
+ y1.y3.x12
+ y1.y2.x12
+ y1.y22.w
+ y1.y23.x1
- y1.u1 =
y1.x2.w
+ y1.y33.x1
+ y1.y2.x12
- x2.u1 =
x22.w
+ x1.u2
+ y3.t
+ y3.x12.x2
+ y3.y42.x12
+ y32.u2
+ y32.u1
+ y32.x2.w
+ y32.x1.w
+ y32.y4.x12
+ y32.y43.x1
+ y33.x1.x2
+ y33.y42.x1
+ y34.w
+ y34.y4.x1
+ y2.t
+ y2.y42.x12
+ y2.y34.x1
+ y2.y35.y4
+ y2.y36
+ y22.x2.w
+ y22.y32.y4.x1
+ y22.y33.x1
+ y23.x1.x2
+ y23.y32.x1
+ y24.y33
+ y1.x13
+ y1.y3.x1.w
+ y1.y22.x12
+ y1.y23.w
+ y1.y24.x1
- y4.t =
y43.x12
+ y3.y4.u1
+ y3.y44.x1
+ y32.y4.x12
+ y32.y43.x1
+ y34.y4.x1
+ y2.y3.u1
+ y2.y3.y4.x12
+ y2.y32.x12
+ y2.y34.x1
+ y22.y3.x12
+ y22.y32.y4.x1
+ y23.y33.y4
+ y23.y34
+ y24.y3.x1
+ y1.y3.x2.w
+ y1.y3.x1.w
+ y1.y33.w
+ y1.y34.x1
+ y1.y2.x2.w
+ y1.y22.x12
- y2.y3.u2 =
y2.y34.x1
+ y22.y32.y4.x1
+ y22.y33.x1
+ y22.y34.y4
+ y22.y35
+ y23.y3.y4.x1
+ y23.y32.x1
+ y23.y33.y4
+ y23.y34
+ y24.y3.x1
+ y24.y32.y4
+ y24.y33
+ y25.y32
+ y1.y3.x2.w
+ y1.y33.w
+ y1.y2.x2.w
+ y1.y22.x12
- y1.t =
y1.y3.x1.w
+ y1.y32.x12
+ y1.y34.x1
+ y1.y2.x1.w
+ y1.y22.x12
+ y1.y23.w
+ y1.y24.x1
- w.u2 =
x2.t
+ y3.x2.u2
+ y3.x1.u2
+ y32.x12.x2
+ y33.x2.w
+ y34.x1.x2
+ y2.x22.w
+ y2.x1.u2
+ y2.x1.x2.w
+ y2.y36.y4
+ y2.y37
+ y22.t
+ y22.x1.x22
+ y22.x12.x2
+ y22.y42.x12
+ y22.y3.y4.x12
+ y22.y32.x12
+ y22.y33.y4.x1
+ y23.x2.w
+ y23.y3.x12
+ y23.y33.x1
+ y23.y34.y4
+ y23.y35
+ y24.x1.x2
+ y24.y3.y4.x1
+ y24.y32.x1
+ y25.y3.x1
+ y25.y32.y4
+ y25.y33
+ y26.y32
+ y1.y3.x13
+ y1.y22.x2.w
+ y1.y22.x1.w
+ y1.y24.w
+ y1.y25.x1
- w.u1 =
x1.t
+ x1.x23
+ x12.x22
+ y42.x13
+ y3.x12.w
+ y3.y43.x12
+ y32.x1.x22
+ y32.y42.x12
+ y34.x12
+ y2.x1.u2
+ y2.x1.x2.w
+ y2.x12.w
+ y2.y32.y4.x12
+ y2.y33.x12
+ y22.x1.x22
+ y22.y32.x12
+ y22.y33.y4.x1
+ y22.y34.x1
+ y23.y3.x12
+ y24.y3.y4.x1
+ y25.y3.x1
+ y1.x22.w
+ y1.y3.x13
+ y1.y32.x2.w
+ y1.y23.x12
- y2.y3.t =
y2.y3.y4.u1
+ y2.y34.y4.x1
+ y22.y3.u1
+ y22.y34.x1
+ y23.y3.x12
+ y23.y32.y4.x1
+ y23.y34.y4
+ y23.y35
+ y24.y3.y4.x1
+ y24.y32.x1
+ y25.y3.x1
+ y1.y34.w
+ y1.y22.x2.w
+ y1.y23.x12
- w.t =
x1.x2.u2
+ x12.u2
+ y3.x2.t
+ y3.x1.t
+ y32.x2.u2
+ y32.x1.u2
+ y32.x12.w
+ y32.y4.x13
+ y33.x1.x22
+ y33.x13
+ y34.x2.w
+ y34.y4.x12
+ y2.x1.t
+ y2.x1.x23
+ y2.x13.x2
+ y2.y42.x13
+ y2.y3.y4.x13
+ y2.y32.x13
+ y2.y37.y4
+ y2.y38
+ y22.y3.y4.u1
+ y22.y33.x12
+ y22.y35.x1
+ y23.x1.x22
+ y23.x12.x2
+ y23.y3.u1
+ y23.y32.x12
+ y23.y33.y4.x1
+ y23.y34.x1
+ y23.y35.y4
+ y23.y36
+ y24.y32.y4.x1
+ y24.y34.y4
+ y24.y35
+ y25.y32.x1
+ y25.y33.y4
+ y25.y34
+ y26.y33
+ y1.y3.x12.w
+ y1.y32.x13
+ y1.y34.x12
+ y1.y2.x22.w
+ y1.y2.x12.w
+ y1.y23.x2.w
+ y1.y23.x1.w
- u22 =
x1.x24
+ x13.x22
+ y32.x13.x2
+ y34.x1.x22
+ y34.x12.x2
+ y34.y42.x12
+ y22.x13.x2
+ y22.y32.x13
+ y22.y33.y4.x12
+ y22.y37.y4
+ y22.y38
+ y23.y32.y4.x12
+ y23.y33.x12
+ y23.y36.y4
+ y23.y37
+ y24.x1.x22
+ y24.x12.x2
+ y24.y34.x1
+ y24.y35.y4
+ y24.y36
+ y25.y34.y4
+ y25.y35
+ y26.y33.y4
+ y26.y34
+ y27.y32.y4
+ y27.y33
+ y28.y32
+ y1.x23.w
+ y1.x13.w
+ y1.y32.x22.w
+ y1.y34.x2.w
+ y1.y36.w
- u1.u2 =
x22.t
+ x12.x23
+ x14.x2
+ y3.x22.u2
+ y3.x1.x2.u2
+ y3.x1.x22.w
+ y3.x12.u2
+ y3.x13.w
+ y32.x1.t
+ y32.x12.x22
+ y32.x14
+ y32.y4.x1.u1
+ y32.y42.x13
+ y33.x22.w
+ y33.x1.u1
+ y33.y4.x13
+ y33.y43.x12
+ y34.x1.x22
+ y34.x12.x2
+ y34.x13
+ y34.y42.x12
+ y35.x1.w
+ y2.x23.w
+ y2.x1.x2.u2
+ y2.x13.w
+ y2.y3.y4.x1.u1
+ y2.y33.y4.u1
+ y2.y34.u1
+ y2.y34.y4.x12
+ y2.y35.x12
+ y2.y38.y4
+ y2.y39
+ y22.x2.t
+ y22.x1.t
+ y22.x1.x23
+ y22.y42.x13
+ y22.y3.x1.u1
+ y22.y32.y4.u1
+ y22.y33.u1
+ y22.y35.y4.x1
+ y22.y36.x1
+ y23.x22.w
+ y23.x12.w
+ y23.y3.y4.u1
+ y23.y32.u1
+ y23.y32.y4.x12
+ y23.y33.x12
+ y23.y36.y4
+ y23.y37
+ y24.x1.x22
+ y24.x12.x2
+ y24.y3.u1
+ y24.y32.x12
+ y24.y33.y4.x1
+ y25.y32.y4.x1
+ y25.y34.y4
+ y25.y35
+ y26.y32.x1
+ y26.y33.y4
+ y26.y34
+ y27.y32.y4
+ y27.y33
+ y28.y32
+ y1.y32.x12.w
+ y1.y34.x2.w
+ y1.y34.x1.w
+ y1.y36.w
+ y1.y2.x14
+ y1.y22.x22.w
+ y1.y24.x2.w
+ y1.y24.x1.w
- u12 =
x1.x24
+ x12.x23
+ x13.x22
+ x15
+ y4.x12.u1
+ y42.x14
+ y43.x1.u1
+ y44.x13
+ y3.y44.u1
+ y3.y47.x1
+ y32.x1.x23
+ y32.x13.x2
+ y32.y4.x1.u1
+ y32.y42.x13
+ y32.y43.u1
+ y33.y4.x13
+ y33.y42.u1
+ y34.x12.x2
+ y34.x13
+ y34.y42.x12
+ y35.y4.x12
+ y35.y43.x1
+ y36.x12
+ y36.y42.x1
+ y2.y4.x14
+ y2.y42.x1.u1
+ y2.y43.x13
+ y2.y44.u1
+ y2.y3.y4.x1.u1
+ y2.y38.y4
+ y22.x1.x23
+ y22.x12.x22
+ y22.x13.x2
+ y22.x14
+ y22.y4.x1.u1
+ y22.y3.y4.x13
+ y22.y34.x12
+ y22.y37.y4
+ y22.y38
+ y23.y4.x13
+ y23.y42.u1
+ y23.y3.x13
+ y23.y35.x1
+ y23.y37
+ y24.x12.x2
+ y24.x13
+ y24.y32.x12
+ y24.y34.x1
+ y25.y3.x12
+ y25.y32.y4.x1
+ y25.y34.y4
+ y25.y35
+ y26.y3.y4.x1
+ y26.y33.y4
+ y28.y3.y4
+ y28.y32
+ y1.x23.w
+ y1.y32.x12.w
+ y1.y34.x2.w
+ y1.y34.x1.w
+ y1.y22.x22.w
+ y1.y22.x12.w
+ y1.y23.x13
+ y1.y24.x2.w
+ y1.y25.x12
+ y42.r
- u2.t =
x1.x23.w
+ x13.x2.w
+ y3.x1.x24
+ y3.x12.x23
+ y3.x13.x22
+ y3.x14.x2
+ y32.x12.u2
+ y32.x13.w
+ y32.y43.x13
+ y33.x2.t
+ y33.x13.x2
+ y33.x14
+ y33.y4.x1.u1
+ y33.y44.x12
+ y34.x2.u2
+ y34.x1.x2.w
+ y34.x12.w
+ y34.y43.x12
+ y35.x1.x22
+ y35.x12.x2
+ y35.x13
+ y36.x2.w
+ y36.y4.x12
+ y37.x1.x2
+ y2.x22.t
+ y2.x1.x2.t
+ y2.x12.x23
+ y2.x14.x2
+ y2.y32.x14
+ y2.y33.x1.u1
+ y2.y34.x13
+ y2.y36.x12
+ y2.y37.y4.x1
+ y2.y38.x1
+ y2.y39.y4
+ y2.y310
+ y22.x23.w
+ y22.x1.x22.w
+ y22.x12.x2.w
+ y22.y32.y4.x13
+ y22.y33.x13
+ y22.y33.y4.u1
+ y22.y35.x12
+ y23.x2.t
+ y23.x1.x23
+ y23.x12.x22
+ y23.x13.x2
+ y23.y32.x13
+ y23.y33.u1
+ y23.y33.y4.x12
+ y23.y37.y4
+ y23.y38
+ y24.x22.w
+ y24.y3.y4.u1
+ y24.y32.y4.x12
+ y24.y34.y4.x1
+ y24.y36.y4
+ y24.y37
+ y25.x1.x22
+ y25.y3.u1
+ y26.y35
+ y1.y3.x23.w
+ y1.y3.x13.w
+ y1.y32.x14
+ y1.y33.x22.w
+ y1.y33.x12.w
+ y1.y34.x13
+ y1.y23.x22.w
+ y1.y23.x12.w
+ y1.y25.x1.w
+ y1.y26.x12
- u1.t =
x1.x22.u2
+ x12.x2.u2
+ x12.x22.w
+ x14.w
+ y42.x12.u1
+ y3.x22.t
+ y3.x1.x2.t
+ y3.x12.t
+ y3.y4.x12.u1
+ y3.y44.x13
+ y32.x22.u2
+ y32.x1.x2.u2
+ y32.x1.x22.w
+ y32.x12.u2
+ y32.x13.w
+ y32.y42.x1.u1
+ y32.y43.x13
+ y32.y44.u1
+ y32.y47.x1
+ y33.x1.t
+ y33.x1.x23
+ y33.x13.x2
+ y33.y4.x1.u1
+ y33.y42.x13
+ y33.y43.u1
+ y34.x22.w
+ y34.x1.u2
+ y34.x1.x2.w
+ y34.y42.u1
+ y34.y43.x12
+ y35.x12.x2
+ y35.x13
+ y36.y43.x1
+ y37.y42.x1
+ y2.x1.x24
+ y2.x12.t
+ y2.x12.x23
+ y2.x13.x22
+ y2.x14.x2
+ y2.y42.x14
+ y2.y3.x12.u1
+ y2.y3.y4.x14
+ y2.y32.x14
+ y2.y32.y4.x1.u1
+ y2.y33.x1.u1
+ y2.y34.x13
+ y2.y38.x1
+ y2.y310
+ y22.x1.x2.u2
+ y22.x1.x22.w
+ y22.x12.u2
+ y22.x12.x2.w
+ y22.x13.w
+ y22.y3.y4.x1.u1
+ y22.y32.y4.x13
+ y22.y33.y4.u1
+ y22.y35.x12
+ y22.y36.y4.x1
+ y22.y37.x1
+ y22.y39
+ y23.x1.t
+ y23.x1.x23
+ y23.y42.x13
+ y23.y3.x1.u1
+ y23.y32.x13
+ y23.y33.u1
+ y23.y33.y4.x12
+ y23.y34.x12
+ y23.y35.y4.x1
+ y23.y38
+ y24.x1.x2.w
+ y24.y3.x13
+ y24.y3.y4.u1
+ y24.y32.u1
+ y24.y34.y4.x1
+ y24.y35.x1
+ y24.y36.y4
+ y25.x12.x2
+ y25.y3.u1
+ y25.y32.x12
+ y25.y35.y4
+ y25.y36
+ y26.y32.y4.x1
+ y26.y33.x1
+ y26.y35
+ y27.y3.y4.x1
+ y27.y33.y4
+ y28.y3.x1
+ y28.y33
+ y1.y3.x13.w
+ y1.y34.x13
+ y1.y35.x1.w
+ y1.y37.w
+ y1.y2.x23.w
+ y1.y2.x13.w
+ y1.y23.x22.w
+ y1.y24.x13
+ y1.y25.x2.w
+ y1.y26.x12
+ y3.y42.r
+ y2.y3.y4.r
- t2 =
x12.x24
+ x13.x23
+ x14.x22
+ x15.x2
+ y44.x14
+ y32.x1.x24
+ y32.x12.x23
+ y32.x13.x22
+ y32.x15
+ y32.y4.x12.u1
+ y32.y42.x14
+ y32.y43.x1.u1
+ y32.y44.x13
+ y32.y46.x12
+ y33.y44.u1
+ y33.y47.x1
+ y34.x12.x22
+ y34.x13.x2
+ y34.x14
+ y34.y4.x1.u1
+ y34.y42.x13
+ y34.y43.u1
+ y34.y44.x12
+ y35.y4.x13
+ y35.y42.u1
+ y36.x12.x2
+ y36.x13
+ y36.y42.x12
+ y37.y4.x12
+ y37.y43.x1
+ y38.x1.x2
+ y38.y42.x1
+ y2.y3.y4.x12.u1
+ y2.y32.x12.u1
+ y2.y32.y4.x14
+ y2.y33.y4.x1.u1
+ y2.y34.x1.u1
+ y2.y35.x13
+ y2.y35.y4.u1
+ y2.y36.y4.x12
+ y2.y37.x12
+ y2.y310.y4
+ y22.x1.x24
+ y22.x14.x2
+ y22.y3.x12.u1
+ y22.y3.y4.x14
+ y22.y32.x14
+ y22.y33.x1.u1
+ y22.y34.x13
+ y22.y34.y4.u1
+ y22.y35.y4.x12
+ y22.y39.y4
+ y22.y310
+ y23.y3.x14
+ y23.y3.y4.x1.u1
+ y23.y32.x1.u1
+ y23.y32.y4.x13
+ y23.y34.y4.x12
+ y23.y35.x12
+ y23.y37.x1
+ y23.y38.y4
+ y23.y39
+ y24.x1.x23
+ y24.x12.x22
+ y24.y3.x1.u1
+ y24.y32.y4.u1
+ y24.y33.u1
+ y24.y34.x12
+ y24.y36.x1
+ y25.y32.u1
+ y25.y32.y4.x12
+ y25.y36.y4
+ y26.y3.y4.x12
+ y26.y33.y4.x1
+ y26.y35.y4
+ y27.y3.x12
+ y27.y32.y4.x1
+ y27.y34.y4
+ y27.y35
+ y28.y32.x1
+ y28.y34
+ y1.y32.x23.w
+ y1.y32.x13.w
+ y1.y34.x12.w
+ y1.y36.x2.w
+ y1.y22.x23.w
+ y1.y22.x13.w
+ y1.y24.x12.w
+ y1.y25.x13
+ y1.y26.x1.w
+ y1.y27.x12
+ y32.y42.r
+ y22.y32.r
This minimal generating set constitutes a Gröbner
basis for the relations ideal.
This cohomology ring was obtained from a calculation
out to degree 18. The cohomology ring approximation
is stable from degree 12 onwards, and
Benson's tests detect stability from degree 12
onwards.
This cohomology ring has dimension 4 and depth 3.
Here is a homogeneous system of parameters:
- h1 =
r
in degree 8
- h2 =
y32
+ y22
in degree 2
- h3 =
x2
+ y42
+ y2.y3
in degree 2
- h4 =
x1
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
-
y42
in degree 2
-
y3.y4
in degree 2
-
y2.y4
in degree 2
-
y2.y3
in degree 2
-
y22
in degree 2
-
y1.y3
in degree 2
-
y1.y2
in degree 2
-
w
in degree 3
-
y3.y42
in degree 3
-
y2.y42
in degree 3
-
y2.y3.y4
in degree 3
-
y22.y4
in degree 3
-
y22.y3
in degree 3
-
y23
in degree 3
-
y1.y22
in degree 3
-
y3.w
in degree 4
-
y2.w
in degree 4
-
y22.y42
in degree 4
-
y22.y3.y4
in degree 4
-
y23.y4
in degree 4
-
y23.y3
in degree 4
-
y1.w
in degree 4
-
u2
in degree 5
-
u1
in degree 5
-
y22.w
in degree 5
-
y23.y3.y4
in degree 5
-
y1.y2.w
in degree 5
-
t
in degree 6
-
y4.u1
in degree 6
-
y3.u2
in degree 6
-
y3.u1
in degree 6
-
y2.u2
in degree 6
-
y2.u1
in degree 6
-
y3.t
in degree 7
-
y3.y4.u1
in degree 7
-
y2.t
in degree 7
-
y2.y4.u1
in degree 7
-
y2.y3.u1
in degree 7
-
y22.u2
in degree 7
-
y22.u1
in degree 7
-
y2.y3.y4.u1
in degree 8
-
y22.t
in degree 8
-
y22.y4.u1
in degree 8
-
y22.y3.u1
in degree 8
-
y23.u1
in degree 8
-
y22.y3.y4.u1
in degree 9
-
y23.y4.u1
in degree 9
-
y23.y3.u1
in degree 9
-
y23.y3.y4.u1
in degree 10
A basis for AnnR/(h1, h2, h3)(h4) is as follows.
-
y1.y3.h
+ y1.y2.h
in degree 4
-
y1.y22.h
in degree 5
-
y1.w.h
+ y1.y2.h2
in degree 6
-
y1.y2.w.h
+ y1.y22.h2
in degree 7
-
y1.h3
in degree 7
-
y1.y2.h3
in degree 8