Simon King
David J. Green
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Singular
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Cohomology of group number 110 of order 128
General information on the group
- The group has 2 minimal generators and exponent 16.
- It is non-abelian.
- It has p-Rank 3.
- Its center has rank 1.
- It has a unique conjugacy class of maximal elementary abelian subgroups, which is of rank 3.
Structure of the cohomology ring
General information
- The cohomology ring is of dimension 3 and depth 1.
- The depth coincides with the Duflot bound.
- The Poincaré series is
t6 − t5 − t4 + 2·t3 − 2·t2 + t − 1 |
| (t − 1)3 · (t2 + 1) · (t4 + 1) |
- The a-invariants are -∞,-5,-3,-3. They were obtained using the filter regular HSOP of the Benson test.
Ring generators
The cohomology ring has 13 minimal generators of maximal degree 8:
- a_1_0, a nilpotent element of degree 1
- a_1_1, a nilpotent element of degree 1
- a_2_0, a nilpotent element of degree 2
- a_2_1, a nilpotent element of degree 2
- b_2_2, an element of degree 2
- b_2_3, an element of degree 2
- b_3_4, an element of degree 3
- b_3_5, an element of degree 3
- a_5_6, a nilpotent element of degree 5
- b_5_9, an element of degree 5
- a_6_6, a nilpotent element of degree 6
- b_6_10, an element of degree 6
- c_8_17, a Duflot regular element of degree 8
Ring relations
There are 53 minimal relations of maximal degree 12:
- a_1_02
- a_1_12
- a_1_0·a_1_1
- a_2_0·a_1_0
- a_2_1·a_1_1
- a_2_1·a_1_0 + a_2_0·a_1_1
- b_2_3·a_1_0 + b_2_2·a_1_1 + a_2_0·a_1_1
- a_2_02
- a_2_0·a_2_1
- a_2_12
- a_1_1·b_3_4 + a_2_0·b_2_3
- a_1_0·b_3_4 + a_2_0·b_2_2
- a_1_1·b_3_5 + a_2_1·b_2_3
- a_1_0·b_3_5 + a_2_1·b_2_2
- b_2_2·b_2_3·a_1_1 + b_2_22·a_1_1
- b_2_22·a_1_0 + a_2_0·b_3_4
- a_2_1·b_3_4 + a_2_0·b_3_5
- a_2_1·b_3_5
- b_3_42 + b_2_23 + a_2_0·b_2_2·b_2_3 + a_2_0·b_2_22
- b_3_52 + b_2_2·b_2_32 + b_2_22·b_2_3 + a_2_1·b_2_32 + a_2_1·b_2_2·b_2_3
- a_2_0·b_2_32 + a_2_0·b_2_2·b_2_3 + a_1_1·a_5_6
- a_1_0·a_5_6
- a_1_1·b_5_9 + a_2_1·b_2_32 + a_2_0·b_2_32 + a_2_0·b_2_2·b_2_3
- a_1_0·b_5_9 + a_2_1·b_2_22
- a_2_0·a_5_6
- b_2_32·b_3_4 + b_2_2·b_5_9 + b_2_2·b_2_3·b_3_4 + b_2_22·b_3_5 + b_2_3·a_5_6
+ b_2_2·a_5_6 + a_2_0·b_2_3·b_3_5 + a_2_0·b_2_3·b_3_4 + a_2_0·b_2_2·b_3_4 + a_2_1·a_5_6
- a_2_0·b_5_9 + a_2_0·b_2_2·b_3_5 + a_2_1·a_5_6
- a_2_1·b_5_9 + a_2_1·a_5_6
- a_6_6·a_1_1 + a_2_1·a_5_6
- a_6_6·a_1_0
- b_6_10·a_1_1 + a_2_0·b_2_3·b_3_5 + a_2_1·a_5_6
- b_6_10·a_1_0 + a_2_0·b_2_3·b_3_5 + a_2_0·b_2_3·b_3_4 + a_2_0·b_2_2·b_3_4 + a_2_1·a_5_6
- b_3_4·b_5_9 + b_2_2·b_3_4·b_3_5 + b_2_22·b_2_32 + b_2_23·b_2_3 + b_3_4·a_5_6
+ b_2_3·a_6_6 + a_2_1·b_2_33 + a_2_0·b_2_23 + b_2_3·a_1_1·a_5_6
- b_3_4·a_5_6 + b_2_2·a_6_6 + a_2_0·b_2_23
- a_2_0·a_6_6
- a_2_1·a_6_6
- b_3_5·b_5_9 + b_3_4·b_5_9 + b_2_3·b_3_4·b_3_5 + b_2_3·b_6_10 + b_2_2·b_3_4·b_3_5
+ b_2_22·b_2_32 + b_2_23·b_2_3 + b_3_5·a_5_6 + b_3_4·a_5_6 + a_2_1·b_2_22·b_2_3 + a_2_0·b_3_4·b_3_5 + a_2_0·b_2_22·b_2_3 + a_2_0·b_2_23 + b_2_3·a_1_1·a_5_6
- b_2_3·b_3_4·b_3_5 + b_2_2·b_6_10 + b_2_23·b_2_3 + b_2_24 + b_3_5·a_5_6 + b_3_4·a_5_6
+ a_2_0·b_3_4·b_3_5 + a_2_0·b_2_22·b_2_3 + a_2_0·b_2_23
- a_2_1·b_2_22·b_2_3 + a_2_0·b_6_10 + a_2_0·b_2_22·b_2_3 + a_2_0·b_2_23
- a_2_1·b_6_10 + a_2_1·b_2_22·b_2_3 + a_2_0·b_3_4·b_3_5
- a_6_6·b_3_4 + b_2_22·a_5_6 + a_2_0·b_2_22·b_3_4 + a_2_1·b_2_3·a_5_6
- b_6_10·b_3_4 + b_2_22·b_2_3·b_3_5 + b_2_22·b_2_3·b_3_4 + b_2_23·b_3_4 + a_6_6·b_3_5
+ b_2_22·a_5_6 + a_2_0·b_2_2·b_2_3·b_3_4 + a_2_0·b_2_22·b_3_4 + a_2_1·b_2_3·a_5_6
- b_6_10·b_3_5 + b_2_2·b_2_3·b_5_9 + b_2_23·b_3_5 + a_6_6·b_3_5 + a_2_1·b_2_3·a_5_6
- a_5_62
- b_5_92 + b_2_2·b_2_34 + b_2_24·b_2_3 + a_5_6·b_5_9 + b_2_32·a_6_6
+ b_2_2·b_3_5·a_5_6 + b_2_2·b_2_3·a_6_6 + b_2_32·a_1_1·a_5_6
- b_5_92 + b_2_2·b_2_34 + b_2_24·b_2_3 + a_2_1·b_2_34 + a_2_0·b_2_2·b_6_10
+ a_2_0·b_2_23·b_2_3 + a_2_0·b_2_24
- a_6_6·a_5_6 + a_2_1·b_2_32·a_5_6
- b_6_10·a_5_6 + a_6_6·b_5_9 + b_2_3·a_6_6·b_3_5 + b_2_2·a_6_6·b_3_5 + b_2_2·b_2_32·a_5_6
+ b_2_23·a_5_6 + a_2_0·b_2_22·b_2_3·b_3_5
- b_6_10·b_5_9 + b_2_2·b_2_33·b_3_5 + b_2_22·b_2_32·b_3_5 + b_2_23·b_5_9
+ b_2_23·b_2_3·b_3_5 + b_2_2·a_6_6·b_3_5 + b_2_2·b_2_32·a_5_6 + b_2_22·b_2_3·a_5_6
- a_6_6·b_5_9 + b_2_2·a_6_6·b_3_5 + b_2_2·b_2_32·a_5_6 + b_2_22·b_2_3·a_5_6
+ a_2_1·b_2_32·a_5_6 + a_2_0·c_8_17·a_1_1
- a_6_62
- b_6_102 + b_2_22·b_2_34 + b_2_23·b_2_33 + b_2_24·b_2_32 + b_2_26
- a_6_6·b_6_10 + b_2_2·b_2_3·b_3_5·a_5_6 + b_2_22·b_2_3·a_6_6 + b_2_23·a_6_6
+ a_2_0·b_2_22·b_6_10 + a_2_0·b_2_24·b_2_3 + a_2_0·b_2_25
Data used for Benson′s test
- Benson′s completion test succeeded in degree 12.
- The completion test was perfect: It applied in the last degree in which a generator or relation was found.
- The following is a filter regular homogeneous system of parameters:
- c_8_17, a Duflot regular element of degree 8
- b_2_32 + b_2_2·b_2_3 + b_2_22, an element of degree 4
- b_3_5, an element of degree 3
- The Raw Filter Degree Type of that HSOP is [-1, 3, 9, 12].
- The filter degree type of any filter regular HSOP is [-1, -2, -3, -3].
- We found that there exists some filter regular HSOP formed by the first term of the above HSOP, together with 2 elements of degree 2.
Restriction maps
Restriction map to the greatest central el. ab. subgp., which is of rank 1
- a_1_0 → 0, an element of degree 1
- a_1_1 → 0, an element of degree 1
- a_2_0 → 0, an element of degree 2
- a_2_1 → 0, an element of degree 2
- b_2_2 → 0, an element of degree 2
- b_2_3 → 0, an element of degree 2
- b_3_4 → 0, an element of degree 3
- b_3_5 → 0, an element of degree 3
- a_5_6 → 0, an element of degree 5
- b_5_9 → 0, an element of degree 5
- a_6_6 → 0, an element of degree 6
- b_6_10 → 0, an element of degree 6
- c_8_17 → c_1_08, an element of degree 8
Restriction map to a maximal el. ab. subgp. of rank 3
- a_1_0 → 0, an element of degree 1
- a_1_1 → 0, an element of degree 1
- a_2_0 → 0, an element of degree 2
- a_2_1 → 0, an element of degree 2
- b_2_2 → c_1_12, an element of degree 2
- b_2_3 → c_1_22, an element of degree 2
- b_3_4 → c_1_13, an element of degree 3
- b_3_5 → c_1_1·c_1_22 + c_1_12·c_1_2, an element of degree 3
- a_5_6 → 0, an element of degree 5
- b_5_9 → c_1_1·c_1_24 + c_1_14·c_1_2, an element of degree 5
- a_6_6 → 0, an element of degree 6
- b_6_10 → c_1_12·c_1_24 + c_1_13·c_1_23 + c_1_14·c_1_22 + c_1_16, an element of degree 6
- c_8_17 → c_1_13·c_1_25 + c_1_14·c_1_24 + c_1_15·c_1_23 + c_1_17·c_1_2 + c_1_18
+ c_1_02·c_1_12·c_1_24 + c_1_02·c_1_14·c_1_22 + c_1_04·c_1_24 + c_1_04·c_1_12·c_1_22 + c_1_04·c_1_14 + c_1_08, an element of degree 8
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