Small group number 242 of order 64
G = Syl2(L3(4)) is Sylow 2-subgroup of L_3(4)
The Hall-Senior number of this group is 183.
G has 4 minimal generators, rank 4 and exponent 4.
The centre has rank 2.
There are 2 conjugacy classes of maximal
elementary abelian subgroups. Their ranks are:
4, 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
- w1 in degree 3
- w2 in degree 3
- v1 in degree 4, a regular element
- v2 in degree 4, a regular element
- t in degree 6
There are 16 minimal relations:
- y42 =
y2.y4
+ y1.y4
+ y1.y3
+ y12
- y3.y4 =
y2.y4
+ y1.y2
- y1.y2.y4 =
y1.y22
+ y12.y3
+ y12.y2
+ y13
- y1.y2.y3 =
y1.y22
+ y12.y3
+ y13
- y1.y4.w2 =
y1.y3.w1
+ y1.y2.w2
+ y1.y2.w1
+ y12.w1
- y1.y4.w1 =
y1.y2.w1
- y1.y3.w2 =
y1.y3.w1
+ y1.y2.w2
+ y1.y2.w1
+ y12.w2
+ y12.w1
- w22 =
y33.w2
+ y2.y32.w2
+ y2.y32.w1
+ y22.y4.w2
+ y22.y3.w2
+ y23.w2
+ y25.y4
+ y1.y25
+ y12.y2.w2
+ y13.w2
+ y13.w1
+ y13.y23
+ y14.y22
+ y32.v1
+ y2.y4.v1
+ y22.v2
+ y22.v1
+ y1.y4.v1
+ y1.y3.v1
+ y12.v1
- w12 =
y33.w2
+ y2.y32.w2
+ y22.y3.w2
+ y22.y3.w1
+ y23.w1
+ y25.y4
+ y1.y22.w2
+ y1.y22.w1
+ y1.y25
+ y12.y2.w2
+ y14.y22
+ y32.v2
+ y2.y4.v1
+ y22.v1
+ y1.y4.v1
+ y1.y3.v1
- y4.t =
y23.y4.w1
+ y1.y23.w2
+ y1.y23.w1
+ y12.y22.w2
+ y12.y22.w1
+ y13.y2.w1
+ y15.y22
+ y22.y4.v1
+ y1.y22.v2
+ y12.y4.v1
+ y12.y3.v1
+ y12.y2.v2
+ y13.v1
- y4.w1.w2 =
y2.t
+ y2.w1.w2
+ y2.y33.w1
+ y23.y4.w1
+ y23.y3.w2
+ y24.w2
+ y24.w1
+ y12.y22.w2
+ y15.y22
+ y22.y4.v2
+ y22.y3.v2
+ y23.v1
+ y12.y4.v1
+ y12.y3.v2
+ y12.y3.v1
+ y13.v2
+ y13.v1
- y3.t =
y3.w1.w2
+ y34.w1
+ y2.t
+ y2.w1.w2
+ y2.y33.w1
+ y22.y32.w2
+ y23.y3.w1
+ y24.w2
+ y24.w1
+ y1.w1.w2
+ y1.y23.w1
+ y13.y2.w2
+ y16.y2
+ y2.y32.v2
+ y22.y3.v2
+ y22.y3.v1
+ y23.v1
+ y1.y22.v2
+ y12.y3.v1
+ y12.y2.v1
+ y13.v2
+ y13.v1
- y1.t =
y1.y23.w1
+ y12.y22.w2
+ y12.y22.w1
+ y13.y2.w2
+ y13.y2.w1
+ y14.w1
+ y16.y2
+ y1.y22.v1
+ y12.y4.v2
+ y13.v2
- w2.t =
y2.y32.w1.w2
+ y2.y35.w2
+ y22.y3.w1.w2
+ y23.t
+ y23.w1.w2
+ y23.y33.w2
+ y23.y33.w1
+ y25.y4.w2
+ y25.y4.w1
+ y25.y3.w2
+ y26.w1
+ y1.y25.w2
+ y1.y25.w1
+ y1.y28
+ y12.y24.w2
+ y12.y24.w1
+ y13.w1.w2
+ y13.y23.w1
+ y13.y26
+ y14.y25
+ y15.y2.w1
+ y15.y24
+ y16.y23
+ y32.w1.v1
+ y2.y4.w2.v2
+ y2.y4.w1.v2
+ y2.y3.w2.v2
+ y2.y34.v2
+ y22.w2.v1
+ y22.w1.v2
+ y22.w1.v1
+ y22.y33.v1
+ y24.y4.v1
+ y24.y3.v1
+ y25.v2
+ y1.y3.w1.v2
+ y1.y2.w1.v2
+ y1.y24.v1
+ y12.w2.v2
+ y12.w1.v2
+ y12.w1.v1
+ y14.y2.v2
+ y14.y2.v1
- w1.t =
y2.y35.w2
+ y2.y35.w1
+ y24.y32.w2
+ y25.y4.w2
+ y25.y4.w1
+ y25.y3.w1
+ y26.w1
+ y28.y4
+ y1.y22.w1.w2
+ y1.y25.w2
+ y12.y2.w1.w2
+ y14.y22.w1
+ y15.y2.w2
+ y15.y24
+ y16.w2
+ y16.y23
+ y17.y22
+ y32.w2.v2
+ y35.v2
+ y35.v1
+ y2.y4.w2.v2
+ y2.y4.w2.v1
+ y2.y4.w1.v2
+ y2.y3.w1.v2
+ y2.y34.v1
+ y22.w2.v1
+ y22.w1.v1
+ y22.y33.v2
+ y22.y33.v1
+ y23.y32.v1
+ y24.y3.v2
+ y24.y3.v1
+ y25.v1
+ y1.y3.w1.v2
+ y1.y3.w1.v1
+ y1.y2.w1.v2
+ y1.y2.w1.v1
+ y1.y24.v1
+ y12.w2.v2
+ y12.w1.v1
+ y12.y23.v2
+ y12.y23.v1
+ y13.y22.v2
+ y14.y2.v1
- t2 =
y2.y35.w1.w2
+ y2.y38.w1
+ y22.y37.w2
+ y22.y37.w1
+ y23.y33.w1.w2
+ y24.y35.w2
+ y24.y35.w1
+ y26.t
+ y28.y4.w2
+ y28.y4.w1
+ y28.y3.w1
+ y211.y4
+ y1.y211
+ y12.y24.w1.w2
+ y12.y27.w2
+ y12.y27.w1
+ y13.y23.w1.w2
+ y13.y26.w2
+ y14.y22.w1.w2
+ y14.y28
+ y15.y2.w1.w2
+ y15.y24.w1
+ y16.y26
+ y17.y22.w2
+ y18.y2.w2
+ y18.y2.w1
+ y19.w2
+ y35.w2.v2
+ y35.w2.v1
+ y38.v2
+ y38.v1
+ y2.y34.w2.v2
+ y2.y34.w2.v1
+ y2.y34.w1.v2
+ y22.y33.w2.v1
+ y22.y33.w1.v1
+ y22.y36.v2
+ y22.y36.v1
+ y23.y35.v2
+ y23.y35.v1
+ y24.y4.w2.v2
+ y24.y4.w1.v2
+ y24.y4.w1.v1
+ y24.y3.w2.v2
+ y24.y3.w1.v2
+ y24.y3.w1.v1
+ y25.w2.v1
+ y25.w1.v2
+ y25.w1.v1
+ y25.y33.v2
+ y25.y33.v1
+ y26.y32.v1
+ y27.y3.v1
+ y28.v2
+ y28.v1
+ y1.y24.w1.v2
+ y1.y27.v2
+ y1.y27.v1
+ y12.y23.w2.v1
+ y12.y23.w1.v1
+ y12.y26.v1
+ y13.y22.w2.v1
+ y13.y22.w1.v1
+ y13.y25.v2
+ y13.y25.v1
+ y14.y2.w1.v2
+ y14.y24.v2
+ y14.y24.v1
+ y15.w2.v2
+ y15.w2.v1
+ y15.y23.v2
+ y15.y23.v1
+ y16.y22.v2
+ y16.y22.v1
+ y34.v1.v2
+ y22.y32.v1.v2
+ y22.y32.v12
+ y23.y4.v1.v2
+ y24.v1.v2
+ y12.y22.v22
+ y12.y22.v1.v2
+ y12.y22.v12
+ y14.v22
+ y14.v1.v2
A minimal Gröbner basis for the relations ideal
consists of this minimal generating set, together with the
following redundant relations:
- y1.y32 =
y1.y2.y4
+ y1.y2.y3
+ y1.y22
+ y12.y3
- y13.y4 =
y13.y2
- y13.y3 =
y13.y2
+ y14
- y12.y3.w1 =
y12.y2.w1
+ y13.w1
This cohomology ring was obtained from a calculation
out to degree 12. 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 2.
Here is a homogeneous system of parameters:
- h1 =
v1
in degree 4
- h2 =
v2
in degree 4
- h3 =
y22
in degree 2
- h4 =
y32
in degree 2
The first
2 terms h1, h2 form
a regular sequence of maximum length.
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.
Data for Benson's test:
-
Raw filter degree type:
-1, -1, 5, 5, 8.
-
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
-
y2.y4
in degree 2
-
y2.y3
in degree 2
-
y1.y4
in degree 2
-
y1.y3
in degree 2
-
y1.y2
in degree 2
-
y12
in degree 2
-
w2
in degree 3
-
w1
in degree 3
-
y12.y4
in degree 3
-
y13
in degree 3
-
y4.w2
in degree 4
-
y4.w1
in degree 4
-
y3.w2
in degree 4
-
y3.w1
in degree 4
-
y2.w2
in degree 4
-
y2.w1
in degree 4
-
y1.w2
in degree 4
-
y1.w1
in degree 4
-
y2.y4.w2
in degree 5
-
y2.y4.w1
in degree 5
-
y2.y3.w2
in degree 5
-
y2.y3.w1
in degree 5
-
y1.y3.w1
in degree 5
-
y1.y2.w2
in degree 5
-
y1.y2.w1
in degree 5
-
y12.w2
in degree 5
-
y12.w1
in degree 5
-
t
in degree 6
-
w1.w2
in degree 6
-
y3.w1.w2
in degree 7
-
y2.t
in degree 7
-
y2.w1.w2
in degree 7
-
y1.w1.w2
in degree 7
-
y2.y3.w1.w2
in degree 8
-
y1.y2.w1.w2
in degree 8
A basis for AnnR/(h1, h2, h3)(h4) is as follows.
-
y2.y4
in degree 2
-
y1.y4
+ y1.y2
in degree 2
-
y1.y3
+ y1.y2
+ y12
in degree 2
-
y12.y4
+ y12.y2
in degree 3
-
y13
+ y1.h
in degree 3
-
y2.y4.w2
in degree 5
-
y2.y4.w1
in degree 5
-
y1.y3.w1
+ y1.y2.w1
+ y12.w1
in degree 5
A basis for AnnR/(h1, h2)(h3) is as follows.
-
y1.y4
+ y1.y2
in degree 2
-
y1.y3
+ y1.y2
+ y12
in degree 2
-
y12.y4
+ y12.y2
in degree 3
-
y12.y3
+ y12.y2
+ y13
in degree 3
-
y1.y3.w1
+ y1.y2.w1
+ y12.w1
in degree 5