Small group number 854 of order 128
G is the group 128gp854
G has 3 minimal generators, rank 4 and exponent 8.
The centre has rank 1.
There are 4 conjugacy classes of maximal
elementary abelian subgroups. Their ranks are:
3, 3, 4, 4.
This cohomology ring calculation is complete.
Ring structure
| Completion information
| Koszul information
| Restriction information
| Poincaré series
The cohomology ring has 14 generators:
- y1 in degree 1, a nilpotent element
- y2 in degree 1
- y3 in degree 1
- x1 in degree 2
- x2 in degree 2
- w1 in degree 3
- w2 in degree 3
- w3 in degree 3
- v in degree 4
- u1 in degree 5
- u2 in degree 5
- t in degree 6
- s in degree 7
- r in degree 8, a regular element
There are 51 minimal relations:
- y1.y3 =
0
- y12 =
0
- y3.x2 =
y1.y22
- y2.y32 =
y22.y3
+ y1.y22
- y1.x1 =
y1.y22
- x1.x2 =
y23.y3
+ y24
+ y1.y23
- y3.w1 =
y1.w2
+ y1.y23
- y2.y3.x1 =
y22.x1
+ y23.y3
+ y24
+ y1.w2
- y22.x2 =
y23.y3
+ y24
+ y1.w1
- y1.w3 =
0
- x2.w3 =
y1.y24
- x2.w2 =
y22.w1
+ y24.y3
+ y25
+ y1.y2.w2
- x1.w1 =
y22.w1
+ y1.y2.w2
- y2.y3.w3 =
y22.w3
+ y1.y24
- y2.y3.w2 =
y22.w2
+ y22.w1
+ y24.y3
+ y25
- y1.v =
y1.y2.w2
+ y1.y2.w1
- w32 =
x13
+ y3.x1.w3
+ y32.v
+ y33.w2
+ y23.w3
+ y23.w2
+ y23.w1
+ y25.y3
+ y1.y25
- w22 =
x1.v
+ y3.u1
+ y32.v
+ y33.w2
+ y2.x1.w3
+ y2.x1.w2
+ y23.w3
+ y23.w2
+ y24.x1
+ y1.y22.w1
+ y1.y25
- w1.w3 =
y1.y22.w1
- w1.w2 =
y2.y3.v
+ y22.v
+ y23.w1
- w12 =
x2.v
+ y2.x2.w1
+ y23.w1
+ y1.x2.w1
+ y1.y22.w1
- y3.u2 =
y3.x1.w2
+ y32.v
+ y24.x1
+ y26
+ y1.y25
- y1.u2 =
y1.x2.w1
+ y1.y22.w1
+ y1.y25
- y1.u1 =
y1.x2.w1
+ y1.y25
- w3.v =
x1.u1
+ y3.t
+ y3.w2.w3
+ y2.w2.w3
+ y2.x13
+ y22.u1
+ y22.x1.w2
+ y22.y3.v
+ y24.w1
+ y25.x1
+ y27
+ y1.y23.w1
+ y1.y26
- x2.u2 =
x2.u1
+ y22.u2
+ y22.x1.w2
+ y22.y3.v
+ y25.x1
+ y27
+ y1.y2.x2.w1
+ y1.y23.w1
- x1.u2 =
x12.w2
+ y3.x1.v
+ y22.u2
+ y22.x1.w2
+ y22.y3.v
+ y23.x12
+ y27
+ y1.y23.w1
+ y1.y26
- y2.y3.u1 =
y22.u1
+ y24.w1
+ y26.y3
+ y27
+ y1.y26
- y1.t =
y1.y23.w1
- w3.u2 =
x1.w2.w3
+ y3.x1.u1
+ y32.t
+ y32.w2.w3
+ y22.w2.w3
+ y22.x13
+ y23.u1
+ y23.x1.w3
+ y23.x1.w2
+ y23.y3.v
+ y25.w3
+ y26.x1
+ y27.y3
+ y1.y24.w1
+ y1.y27
- w3.u1 =
x12.v
+ y3.s
+ y3.w2.v
+ y32.t
+ y32.w2.w3
+ y32.x1.v
+ y33.x1.w2
+ y34.v
+ y2.x12.w3
+ y2.x12.w2
+ y2.y3.t
+ y23.x1.w2
+ y24.v
+ y24.x12
+ y25.w2
+ y25.w1
- w2.u2 =
x12.v
+ y3.w2.v
+ y3.x1.u1
+ y32.x1.v
+ y33.x1.w2
+ y2.x12.w3
+ y2.x12.w2
+ y2.y3.t
+ y22.t
+ y23.u2
+ y23.x1.w3
+ y23.x1.w2
+ y23.y3.v
+ y24.x12
+ y25.w2
+ y25.w1
+ y26.x1
+ y27.y3
+ y1.y27
- w1.u2 =
x2.t
+ y2.x2.u1
+ y2.x22.w1
+ y23.y3.v
+ y24.v
+ y1.x22.w1
+ y1.y24.w1
+ y1.y27
- w1.u1 =
x2.t
+ y2.x2.u1
+ y2.x22.w1
+ y2.y3.t
+ y22.t
+ y23.y3.v
+ y24.v
+ y25.w1
+ y27.y3
+ y28
+ y1.x22.w1
+ y1.y24.w1
+ y1.y27
- y1.s =
y1.y27
- v.u2 =
w1.t
+ x1.w2.v
+ y3.v2
+ y2.x22.v
+ y23.x1.v
+ y25.v
+ y26.w1
+ y1.y2.x22.w1
+ y1.y25.w1
- w3.t =
x1.s
+ x1.w2.v
+ x12.u1
+ x13.w2
+ y3.v2
+ y3.x1.w2.w3
+ y3.x12.v
+ y32.x12.w2
+ y34.u1
+ y35.v
+ y36.w2
+ y2.x1.t
+ y2.x1.w2.w3
+ y2.x12.v
+ y2.x14
+ y22.s
+ y22.w2.v
+ y22.x1.u1
+ y22.x12.w3
+ y22.x12.w2
+ y22.y3.t
+ y23.t
+ y23.w2.w3
+ y23.x13
+ y24.u1
+ y24.x1.w3
+ y24.x1.w2
+ y24.y3.v
+ y25.v
+ y26.w3
+ y27.x1
+ y28.y3
+ y29
- x2.s =
x2.w1.v
+ x22.u1
+ x23.w1
+ y2.x2.t
+ y2.x22.v
+ y24.y3.v
+ y25.v
+ y1.y2.x22.w1
- y2.y3.s =
y22.s
+ y22.w1.v
+ y22.y3.t
+ y23.t
+ y28.y3
+ y29
+ y1.y25.w1
- u22 =
x2.v2
+ x23.v
+ x13.v
+ y3.x12.u1
+ y32.v2
+ y32.x12.v
+ y33.x12.w2
+ y2.x23.w1
+ y2.x13.w3
+ y2.x13.w2
+ y23.x12.w3
+ y23.x12.w2
+ y24.x13
+ y26.x12
+ y27.w1
+ y29.y3
+ y1.x23.w1
+ y1.y26.w1
+ y1.y29
- u1.u2 =
x2.v2
+ x23.v
+ x1.w2.u1
+ y3.v.u1
+ y2.x23.w1
+ y2.y3.v2
+ y22.v2
+ y23.x1.u1
+ y23.y3.t
+ y24.t
+ y25.u2
+ y25.u1
+ y25.x1.w2
+ y26.v
+ y28.x1
+ y29.y3
+ y1.x23.w1
+ y1.y29
- u12 =
x2.v2
+ x23.v
+ x1.v2
+ y3.v.u1
+ y32.w2.u1
+ y32.x1.t
+ y32.x14
+ y33.x1.u1
+ y33.x12.w3
+ y34.t
+ y34.x1.v
+ y36.v
+ y2.x23.w1
+ y22.w2.u1
+ y22.x14
+ y23.w2.v
+ y23.w1.v
+ y23.x12.w3
+ y23.x12.w2
+ y23.y3.t
+ y24.w2.w3
+ y25.u1
+ y25.y3.v
+ y26.x12
+ y27.w3
+ y27.w2
+ y28.x1
+ y1.x23.w1
+ y32.r
- w3.s =
x1.w2.u1
+ x12.t
+ x12.w2.w3
+ x13.v
+ y3.v.u1
+ y3.w2.t
+ y3.x12.u1
+ y32.v2
+ y32.w2.u1
+ y32.x1.t
+ y32.x12.v
+ y33.s
+ y34.t
+ y34.x1.v
+ y35.x1.w2
+ y36.v
+ y2.x1.s
+ y2.x1.w2.v
+ y2.x12.u1
+ y2.y3.v2
+ y22.x14
+ y23.w2.v
+ y23.w1.v
+ y23.x12.w2
+ y23.y3.t
+ y24.w2.w3
+ y25.u1
+ y25.x1.w3
+ y25.x1.w2
+ y25.y3.v
+ y26.x12
+ y27.w2
+ y27.w1
+ y28.x1
+ y1.y26.w1
+ y1.y29
- w1.s =
x2.v2
+ x22.t
+ x23.v
+ y2.w1.t
+ y2.x22.u1
+ y23.y3.t
+ y24.t
+ y25.y3.v
+ y26.v
+ y29.y3
+ y210
+ y1.y29
- u2.t =
w1.v2
+ x22.w1.v
+ x1.w2.t
+ y3.v.t
+ y2.x2.v2
+ y2.x22.t
+ y22.y3.v2
+ y23.v2
+ y23.x1.t
+ y25.t
+ y26.u2
+ y26.x1.w2
+ y26.y3.v
+ y29.x1
+ y210.y3
+ y1.y2.x23.w1
+ y1.y210
- u1.t =
v.s
+ w2.v2
+ x2.w1.t
+ x1.v.u1
+ x12.w2.v
+ y3.v.t
+ y3.w2.s
+ y3.x12.t
+ y3.x15
+ y32.v.u1
+ y32.x12.u1
+ y32.x13.w3
+ y33.x1.t
+ y34.x1.u1
+ y36.x1.w2
+ y2.v.t
+ y2.w2.s
+ y2.x22.t
+ y2.x23.v
+ y2.x12.t
+ y22.v.u1
+ y22.w2.t
+ y22.x1.w2.v
+ y22.x12.u1
+ y22.x13.w3
+ y22.x13.w2
+ y23.w2.u1
+ y23.x1.w2.w3
+ y24.w2.v
+ y24.x1.u1
+ y24.x12.w3
+ y24.y3.t
+ y25.t
+ y25.w2.w3
+ y26.x1.w2
+ y28.w3
+ y28.w1
+ y29.x1
+ y210.y3
+ y211
+ y3.x1.r
+ y22.y3.r
- t2 =
v3
+ x22.v2
+ x1.v.t
+ x13.t
+ x14.v
+ x16
+ y3.w2.v2
+ y3.x1.w2.t
+ y3.x14.w3
+ y32.x1.v2
+ y32.x12.t
+ y33.v.u1
+ y33.x1.w2.v
+ y33.x13.w2
+ y34.v2
+ y34.w2.u1
+ y34.x12.v
+ y36.x1.v
+ y37.u1
+ y38.v
+ y39.w2
+ y2.w2.v2
+ y2.w1.v2
+ y2.x1.w2.t
+ y2.x13.u1
+ y2.x14.w3
+ y2.x14.w2
+ y22.v.t
+ y22.x1.v2
+ y22.x12.t
+ y22.x12.w2.w3
+ y22.x13.v
+ y23.v.u1
+ y23.w1.t
+ y23.x13.w3
+ y24.w2.u1
+ y24.x1.t
+ y24.x12.v
+ y24.x14
+ y25.w2.v
+ y25.x1.u1
+ y26.w2.w3
+ y29.w3
+ y29.w1
+ y210.x1
+ y211.y3
+ y1.y28.w1
+ y1.y211
+ x12.r
+ y24.r
- u2.s =
x2.v.t
+ x22.v2
+ x23.t
+ x24.v
+ x1.w2.s
+ y3.v.s
+ y2.w1.v2
+ y2.x23.u1
+ y23.x1.s
+ y23.y3.v2
+ y24.v2
+ y25.s
+ y29.w1
+ y1.y28.w1
- u1.s =
w2.v.u1
+ x2.v.t
+ x22.v2
+ x23.t
+ x24.v
+ x1.v.t
+ x12.v2
+ x12.w2.u1
+ y3.x1.w2.t
+ y3.x12.s
+ y3.x14.w3
+ y3.x14.w2
+ y32.w2.s
+ y32.x13.v
+ y33.w2.t
+ y33.x1.s
+ y33.x12.u1
+ y34.x1.w2.w3
+ y34.x12.v
+ y35.s
+ y35.w2.v
+ y36.t
+ y37.u1
+ y37.x1.w2
+ y39.w2
+ y2.v.s
+ y2.w2.v2
+ y2.x2.w1.t
+ y2.x22.w1.v
+ y2.x23.u1
+ y2.x1.w2.t
+ y2.x12.s
+ y2.x12.w2.v
+ y2.x14.w2
+ y2.y3.v.t
+ y22.v.t
+ y22.x12.w2.w3
+ y23.v.u1
+ y23.w2.t
+ y23.x1.s
+ y23.x13.w3
+ y24.v2
+ y24.w2.u1
+ y24.x1.t
+ y24.x1.w2.w3
+ y25.s
+ y25.w2.v
+ y25.x1.u1
+ y25.y3.t
+ y26.x13
+ y27.x1.w3
+ y27.y3.v
+ y28.x12
+ y29.w3
+ y210.x1
+ y1.y28.w1
+ y3.w3.r
+ y32.x1.r
+ y22.x1.r
+ y23.y3.r
+ y24.r
+ y1.w2.r
+ y1.y23.r
- t.s =
v2.u1
+ w2.v.t
+ x2.w1.v2
+ x22.w1.t
+ x23.w1.v
+ x12.w2.t
+ x13.s
+ x13.w2.v
+ x15.w3
+ x15.w2
+ y3.v3
+ y3.x1.w2.s
+ y3.x12.w2.u1
+ y3.x14.v
+ y32.x12.s
+ y32.x13.u1
+ y33.v.t
+ y33.x12.w2.w3
+ y33.x13.v
+ y34.v.u1
+ y34.x1.s
+ y34.x1.w2.v
+ y35.v2
+ y35.x14
+ y36.w2.v
+ y36.x12.w3
+ y36.x12.w2
+ y37.t
+ y37.x1.v
+ y38.x1.w2
+ y39.v
+ y2.v3
+ y2.x2.v.t
+ y2.x22.v2
+ y2.x23.t
+ y2.x1.w2.s
+ y2.x12.w2.u1
+ y2.x13.w2.w3
+ y22.v.s
+ y22.w1.v2
+ y22.x1.v.u1
+ y22.x12.s
+ y22.x12.w2.v
+ y22.x13.u1
+ y22.x14.w3
+ y22.x14.w2
+ y23.v.t
+ y23.w2.s
+ y23.x12.t
+ y24.v.u1
+ y24.w2.t
+ y24.w1.t
+ y24.x1.w2.v
+ y24.x12.u1
+ y24.y3.v2
+ y25.v2
+ y25.x12.v
+ y26.s
+ y26.w2.v
+ y26.x12.w3
+ y26.x12.w2
+ y26.y3.t
+ y27.x1.v
+ y28.u1
+ y28.x1.w3
+ y210.w3
+ y212.y3
+ y213
+ y1.y2.x24.w1
+ y1.y212
+ x1.w3.r
+ y3.x12.r
+ y35.r
+ y2.x12.r
+ y22.w3.r
+ y25.r
+ y1.y24.r
- s2 =
x2.v3
+ x23.v2
+ x12.v.t
+ x13.v2
+ x14.t
+ x17
+ y3.x1.v.s
+ y3.x12.w2.t
+ y3.x13.s
+ y3.x14.u1
+ y3.x15.w2
+ y32.x1.v.t
+ y32.x1.w2.s
+ y32.x12.w2.u1
+ y32.x13.t
+ y32.x14.v
+ y33.x1.v.u1
+ y33.x12.s
+ y33.x12.w2.v
+ y33.x14.w2
+ y34.v.t
+ y34.x1.v2
+ y34.x1.w2.u1
+ y34.x12.t
+ y34.x12.w2.w3
+ y34.x13.v
+ y35.w2.t
+ y35.x1.s
+ y35.x12.u1
+ y36.x12.v
+ y36.x14
+ y37.w2.v
+ y37.x12.w3
+ y38.t
+ y38.x1.v
+ y39.x1.w2
+ y310.v
+ y2.x2.w1.v2
+ y2.x12.v.u1
+ y2.x12.w2.t
+ y2.x14.u1
+ y22.v3
+ y22.x1.w2.s
+ y22.x12.v2
+ y22.x12.w2.u1
+ y22.x13.t
+ y23.v.s
+ y23.x1.v.u1
+ y23.x14.w3
+ y24.x1.v2
+ y24.x12.t
+ y25.x1.s
+ y25.x12.u1
+ y25.x13.w3
+ y26.w2.u1
+ y26.x1.t
+ y26.x12.v
+ y26.x14
+ y27.x1.u1
+ y27.x12.w3
+ y27.x12.w2
+ y27.y3.t
+ y28.t
+ y28.w2.w3
+ y28.x13
+ y29.x1.w3
+ y29.y3.v
+ y210.x12
+ y211.w3
+ y211.w2
+ y212.x1
+ y213.y3
+ x13.r
+ y3.x1.w3.r
+ y32.v.r
+ y32.x12.r
+ y33.w2.r
+ y36.r
+ y22.x12.r
+ y23.w3.r
+ y23.w2.r
+ y23.w1.r
+ y25.y3.r
+ y26.r
+ y1.y25.r
A minimal Gröbner basis for the relations ideal
consists of this minimal generating set, together with the
following redundant relations:
- y1.y22.w2 =
y1.y22.w1
+ y1.y25
- x2.v.u1 =
x2.w1.t
+ y2.x23.v
+ y22.w1.t
+ y24.w1.v
+ y1.y2.x23.w1
+ y1.y210
This cohomology ring was obtained from a calculation
out to degree 18. The cohomology ring approximation
is stable from degree 14 onwards, and
Benson's tests detect stability from degree 14
onwards.
This cohomology ring has dimension 4 and depth 2.
Here is a homogeneous system of parameters:
- h1 =
r
in degree 8
- h2 =
x2
+ y32
in degree 2
- h3 =
v
in degree 4
- h4 =
x1
+ y22
in degree 2
The first
2 terms h1, h2 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, 5, 10, 12.
-
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
-
y3
in degree 1
-
y2
in degree 1
-
y1
in degree 1
-
y32
in degree 2
-
y2.y3
in degree 2
-
y22
in degree 2
-
y1.y2
in degree 2
-
w3
in degree 3
-
w2
in degree 3
-
w1
in degree 3
-
y22.y3
in degree 3
-
y23
in degree 3
-
y1.y22
in degree 3
-
y3.w3
in degree 4
-
y3.w2
in degree 4
-
y2.w3
in degree 4
-
y2.w2
in degree 4
-
y2.w1
in degree 4
-
y1.y23
in degree 4
-
u2
in degree 5
-
u1
in degree 5
-
y22.w3
in degree 5
-
y22.w2
in degree 5
-
y22.w1
in degree 5
-
t
in degree 6
-
w2.w3
in degree 6
-
y3.u1
in degree 6
-
y2.u2
in degree 6
-
y2.u1
in degree 6
-
y23.w1
in degree 6
-
s
in degree 7
-
y3.w2.w3
in degree 7
-
y2.t
in degree 7
-
y2.w2.w3
in degree 7
-
y22.u2
in degree 7
-
y22.u1
in degree 7
-
w2.u1
in degree 8
-
y3.s
in degree 8
-
y2.s
in degree 8
-
y22.t
in degree 8
-
y22.w2.w3
in degree 8
-
y23.u1
in degree 8
-
w2.t
in degree 9
-
y3.w2.u1
in degree 9
-
y2.w2.u1
in degree 9
-
y22.s
in degree 9
-
y23.t
in degree 9
-
w2.s
in degree 10
-
y2.w2.t
in degree 10
-
y22.w2.u1
in degree 10
-
y3.w2.s
in degree 11
-
y2.w2.s
in degree 11
-
y22.w2.s
in degree 12
A basis for AnnR/(h1, h2, h3)(h4) is as follows.
-
y1
in degree 1
-
y1.y2
in degree 2
-
w1
+ y22.y3
in degree 3
-
y23
in degree 3
-
y1.y22
in degree 3
-
y2.w1
+ y23.y3
in degree 4
-
y1.y23
in degree 4
-
y32.h
in degree 4
-
y2.y3.h
+ y22.h
in degree 4
-
u2
+ y22.w2
+ w2.h
in degree 5
-
y22.w1
+ y24.y3
in degree 5
-
y22.y3.h
+ y23.h
in degree 5
-
y2.u2
+ y23.w2
+ y2.w2.h
in degree 6
-
y23.w1
+ y25.y3
in degree 6
-
y22.u2
+ y24.w2
+ y22.w2.h
in degree 7
-
y22.t
+ y2.u1.h
+ y22.h3
in degree 8
-
y22.w2.w3
+ y3.u1.h
+ y22.h3
in degree 8
-
y23.u1
in degree 8
-
y3.w2.u1
+ y22.w2.h2
in degree 9
-
y23.t
in degree 9
-
y22.u1.h
in degree 9
-
y22.w2.u1
in degree 10
A basis for AnnR/(h1, h2)(h3) is as follows.
-
y1.y2
in degree 2
-
y1.y22
in degree 3
-
y1.w2
in degree 4
-
y1.w1
in degree 4
-
y1.y23
in degree 4
-
y1.y2.w1
in degree 5
-
y1.h
in degree 5