Simon King
David J. Green
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Singular
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Cohomology of group number 830 of order 128
General information on the group
- The group has 3 minimal generators and exponent 8.
- It is non-abelian.
- It has p-Rank 3.
- Its center has rank 1.
- It has 2 conjugacy classes of maximal elementary abelian subgroups, which are all of rank 3.
Structure of the cohomology ring
General information
- The cohomology ring is of dimension 3 and depth 2.
- The depth exceeds the Duflot bound, which is 1.
- The Poincaré series is
- The a-invariants are -∞,-∞,-3,-3. They were obtained using the filter regular HSOP of the Benson test.
Ring generators
The cohomology ring has 14 minimal generators of maximal degree 8:
- a_1_0, a nilpotent element of degree 1
- a_1_1, a nilpotent element of degree 1
- b_1_2, an element of degree 1
- b_2_3, an element of degree 2
- b_2_4, an element of degree 2
- a_3_6, a nilpotent element of degree 3
- a_4_5, a nilpotent element of degree 4
- a_4_6, a nilpotent element of degree 4
- b_5_11, an element of degree 5
- b_5_12, an element of degree 5
- b_5_13, an element of degree 5
- a_7_16, a nilpotent element of degree 7
- b_8_25, an element of degree 8
- c_8_26, a Duflot regular element of degree 8
Ring relations
There are 61 minimal relations of maximal degree 16:
- a_1_12 + a_1_0·a_1_1 + a_1_02
- a_1_1·b_1_2
- a_1_0·b_1_2 + a_1_12
- b_2_4·b_1_2 + b_2_4·a_1_1 + b_2_4·a_1_0 + b_2_3·a_1_1
- a_1_1·a_3_6 + b_2_4·a_1_0·a_1_1 + b_2_3·a_1_02
- a_1_0·a_3_6 + b_2_3·a_1_02
- b_2_3·b_2_4·a_1_1 + b_2_32·a_1_1
- b_1_22·a_3_6 + a_4_5·b_1_2 + b_2_4·a_3_6 + b_2_42·a_1_0 + b_2_32·a_1_1
- a_4_5·a_1_1
- b_2_4·a_3_6 + b_2_42·a_1_0 + b_2_32·a_1_1 + a_4_5·a_1_0
- b_1_22·a_3_6 + a_4_6·b_1_2 + b_2_4·a_3_6 + b_2_42·a_1_0 + b_2_3·a_3_6
+ b_2_3·b_2_4·a_1_0
- b_2_4·a_3_6 + b_2_42·a_1_0 + b_2_32·a_1_1 + a_4_6·a_1_1
- a_4_6·a_1_0
- a_3_62
- a_1_1·b_5_11 + b_2_32·a_1_02
- b_1_2·b_5_12 + b_1_2·b_5_11 + b_2_32·b_1_22 + a_1_0·b_5_11 + a_4_5·b_1_22
+ b_2_3·a_4_5 + b_2_32·a_1_02
- a_1_0·b_5_12 + b_2_3·b_1_2·a_3_6 + b_2_3·a_4_5 + b_2_42·a_1_0·a_1_1 + b_2_32·a_1_02
- b_1_2·b_5_13 + b_1_2·b_5_11 + a_4_5·b_1_22 + b_2_4·a_4_5
- a_1_1·b_5_13 + a_1_0·b_5_11 + b_2_4·a_4_6 + b_2_4·a_4_5 + b_2_3·b_1_2·a_3_6 + b_2_3·a_4_5
+ b_2_42·a_1_0·a_1_1
- a_1_1·b_5_12 + a_1_0·b_5_13 + b_2_4·a_4_6 + b_2_3·b_1_2·a_3_6 + b_2_3·a_4_5
- a_4_5·a_3_6 + b_2_4·a_4_5·a_1_0
- a_4_6·a_3_6 + b_2_3·a_4_5·a_1_0
- b_2_4·b_5_12 + b_2_3·b_5_13 + b_2_3·b_5_11 + b_2_43·a_1_1 + b_2_3·a_4_5·b_1_2
+ b_2_32·b_2_4·a_1_0 + b_2_33·a_1_0 + b_2_3·a_4_5·a_1_0
- a_4_52
- a_4_62
- a_4_5·a_4_6
- a_3_6·b_5_12 + a_3_6·b_5_11 + b_2_4·a_1_0·b_5_11 + b_2_3·a_1_0·b_5_11
+ b_2_3·b_2_4·a_4_6 + b_2_32·a_4_5 + b_2_43·a_1_0·a_1_1
- a_3_6·b_5_13 + a_3_6·b_5_11 + b_2_4·a_1_0·b_5_11 + b_2_42·a_4_6 + b_2_3·b_2_4·a_4_5
+ b_2_43·a_1_0·a_1_1
- a_3_6·b_5_11 + b_1_2·a_7_16 + b_2_4·a_1_0·b_5_11 + b_2_3·a_4_5·b_1_22
- a_1_1·a_7_16 + b_2_43·a_1_0·a_1_1 + b_2_33·a_1_02
- a_1_0·a_7_16 + b_2_43·a_1_0·a_1_1 + b_2_33·a_1_02
- a_4_6·b_5_12 + a_4_6·b_5_11 + a_4_5·b_5_12 + a_4_5·b_5_11 + b_2_32·b_2_42·a_1_0
+ b_2_33·a_3_6 + b_2_34·a_1_1 + b_2_42·a_4_5·a_1_0
- a_4_6·b_5_13 + a_4_6·b_5_12 + b_2_3·b_2_43·a_1_0 + b_2_32·a_4_5·b_1_2 + b_2_33·a_3_6
+ b_2_34·a_1_1
- a_4_5·b_5_13 + a_4_5·b_5_11 + b_2_3·b_2_43·a_1_0 + b_2_32·b_2_42·a_1_0
+ b_2_42·a_4_5·a_1_0
- b_1_22·a_7_16 + a_4_6·b_5_12 + a_4_6·b_5_11 + a_4_5·b_5_11 + b_2_3·a_4_5·b_1_23
+ b_2_32·a_4_5·b_1_2 + b_2_33·a_3_6 + b_2_33·b_2_4·a_1_0 + b_2_34·a_1_1 + b_2_42·a_4_5·a_1_0
- a_4_6·b_5_11 + a_4_5·b_5_11 + b_2_3·a_7_16 + b_2_32·a_4_5·b_1_2 + b_2_33·b_2_4·a_1_0
+ b_2_34·a_1_1
- a_4_6·b_5_12 + a_4_6·b_5_11 + b_2_4·a_7_16 + b_2_44·a_1_1 + b_2_3·b_2_43·a_1_0
+ b_2_32·a_4_5·b_1_2 + b_2_32·b_2_42·a_1_0 + b_2_33·a_3_6 + b_2_34·a_1_1 + b_2_32·a_4_5·a_1_0
- b_8_25·b_1_2 + b_2_3·b_1_22·b_5_11 + a_4_6·b_5_12 + a_4_6·b_5_11 + a_4_5·b_1_25
+ b_2_44·a_1_1 + b_2_44·a_1_0 + b_2_32·b_2_42·a_1_0 + b_2_33·a_3_6 + b_2_33·b_2_4·a_1_0
- b_8_25·a_1_1 + b_2_44·a_1_1 + b_2_34·a_1_1 + b_2_42·a_4_5·a_1_0
- b_8_25·a_1_0 + a_4_6·b_5_12 + a_4_6·b_5_11 + b_2_44·a_1_0 + b_2_32·a_4_5·b_1_2
+ b_2_32·b_2_42·a_1_0 + b_2_33·a_3_6 + b_2_33·b_2_4·a_1_0 + b_2_34·a_1_1 + b_2_42·a_4_5·a_1_0
- b_5_132 + b_5_12·b_5_13 + b_5_122 + b_5_11·b_5_12 + b_2_3·b_2_44 + b_2_32·b_2_43
+ b_2_34·b_1_22 + a_4_5·b_1_2·b_5_11 + b_2_42·a_1_0·b_5_11 + b_2_43·a_4_5 + b_2_3·b_2_42·a_4_5 + b_2_32·a_4_5·b_1_22 + b_2_33·b_1_2·a_3_6 + b_2_33·a_4_5 + b_2_44·a_1_0·a_1_1
- a_3_6·a_7_16 + b_2_44·a_1_0·a_1_1
- b_5_112 + b_2_3·b_1_23·b_5_11 + b_2_32·b_1_2·b_5_11 + b_2_32·b_1_26
+ b_2_32·b_2_43 + b_2_33·b_1_24 + b_2_34·b_1_22 + b_2_34·b_2_4 + a_4_5·b_1_2·b_5_11 + b_2_3·a_4_5·b_1_24 + b_2_3·b_2_42·a_4_6 + b_2_3·b_2_42·a_4_5 + b_2_32·a_1_0·b_5_11 + b_2_32·b_2_4·a_4_6 + b_2_33·b_1_2·a_3_6 + b_2_33·a_4_5 + b_2_44·a_1_0·a_1_1 + c_8_26·b_1_22
- b_5_122 + b_5_112 + b_2_32·b_2_43 + b_2_33·b_2_42 + b_2_34·b_1_22
+ b_2_3·b_2_42·a_4_6 + b_2_3·b_2_42·a_4_5 + b_2_34·a_1_02 + c_8_26·a_1_0·a_1_1
- b_5_12·b_5_13 + b_5_11·b_5_12 + b_2_32·b_2_43 + b_2_33·b_2_42 + a_4_5·b_1_2·b_5_11
+ b_2_42·a_1_0·b_5_11 + b_2_43·a_4_6 + b_2_43·a_4_5 + b_2_3·b_2_42·a_4_6 + b_2_3·b_2_42·a_4_5 + b_2_32·a_4_5·b_1_22 + b_2_33·b_1_2·a_3_6 + b_2_33·a_4_5 + b_2_44·a_1_0·a_1_1 + c_8_26·a_1_02
- b_5_12·b_5_13 + b_5_122 + b_2_3·b_8_25 + b_2_3·b_2_44 + b_2_32·b_2_43
+ b_2_33·b_2_42 + b_2_34·b_1_22 + b_2_34·b_2_4 + b_2_42·a_1_0·b_5_11 + b_2_43·a_4_6 + b_2_43·a_4_5 + b_2_3·b_1_2·a_7_16 + b_2_3·a_4_5·b_1_24 + b_2_3·b_2_42·a_4_6 + b_2_32·a_1_0·b_5_11 + b_2_32·b_2_4·a_4_6 + b_2_33·a_4_5
- b_5_11·b_5_13 + b_5_112 + b_2_4·b_8_25 + b_2_45 + b_2_32·b_2_43
+ a_4_5·b_1_2·b_5_11 + b_2_42·a_1_0·b_5_11 + b_2_43·a_4_6 + b_2_3·b_2_42·a_4_5 + b_2_32·b_2_4·a_4_6 + b_2_33·b_1_2·a_3_6 + b_2_33·a_4_5 + b_2_34·a_1_02
- a_4_6·a_7_16 + b_2_43·a_4_5·a_1_0
- a_4_5·a_7_16 + b_2_33·a_4_5·a_1_0
- b_8_25·a_3_6 + b_2_42·a_7_16 + b_2_45·a_1_1 + b_2_45·a_1_0 + b_2_3·a_4_5·b_5_11
+ b_2_3·b_2_4·a_7_16 + b_2_3·b_2_44·a_1_0 + b_2_32·b_2_43·a_1_0 + b_2_34·b_2_4·a_1_0 + b_2_35·a_1_1 + b_2_33·a_4_5·a_1_0
- b_5_12·a_7_16 + b_5_11·a_7_16 + b_2_3·b_2_43·a_4_6 + b_2_3·b_2_43·a_4_5
+ b_2_32·b_1_2·a_7_16 + b_2_32·b_2_42·a_4_5 + b_2_33·b_2_4·a_4_5 + b_2_45·a_1_0·a_1_1 + b_2_35·a_1_02
- b_5_13·a_7_16 + b_5_11·a_7_16 + b_2_43·a_1_0·b_5_11 + b_2_44·a_4_6 + b_2_44·a_4_5
+ b_2_3·b_2_43·a_4_6 + b_2_3·b_2_43·a_4_5 + b_2_32·b_2_42·a_4_6 + b_2_32·b_2_42·a_4_5 + b_2_45·a_1_0·a_1_1
- b_5_11·a_7_16 + b_2_3·b_2_43·a_4_6 + b_2_3·b_2_43·a_4_5 + b_2_32·b_1_2·a_7_16
+ b_2_32·a_4_5·b_1_24 + b_2_32·b_2_42·a_4_6 + b_2_32·b_2_42·a_4_5 + b_2_33·a_1_0·b_5_11 + b_2_33·b_2_4·a_4_5 + b_2_34·a_4_5 + c_8_26·b_1_2·a_3_6 + b_2_4·c_8_26·a_1_0·a_1_1 + b_2_3·c_8_26·a_1_02
- a_4_6·b_8_25 + b_2_44·a_4_6 + b_2_3·a_4_5·b_1_2·b_5_11 + b_2_3·b_2_43·a_4_6
+ b_2_3·b_2_43·a_4_5 + b_2_32·b_1_2·a_7_16 + b_2_32·b_2_42·a_4_6 + b_2_33·a_4_5·b_1_22 + b_2_33·b_2_4·a_4_6 + b_2_33·b_2_4·a_4_5 + b_2_35·a_1_02
- a_4_5·b_8_25 + b_2_44·a_4_5 + b_2_3·a_4_5·b_1_2·b_5_11 + b_2_3·b_2_43·a_4_6
+ b_2_3·b_2_43·a_4_5 + b_2_32·b_2_42·a_4_6 + b_2_32·b_2_42·a_4_5 + b_2_33·b_2_4·a_4_5
- b_8_25·b_5_11 + b_2_44·b_5_11 + b_2_32·b_1_24·b_5_11 + b_2_32·b_2_42·b_5_13
+ b_2_33·b_1_22·b_5_11 + b_2_33·b_1_27 + b_2_34·b_5_13 + b_2_34·b_5_11 + b_2_34·b_1_25 + b_2_35·b_1_23 + a_4_5·b_1_24·b_5_11 + b_2_43·a_7_16 + b_2_46·a_1_1 + b_2_3·a_4_5·b_1_22·b_5_11 + b_2_3·b_2_42·a_7_16 + b_2_3·b_2_45·a_1_0 + b_2_32·a_4_5·b_5_11 + b_2_32·a_4_5·b_1_25 + b_2_32·b_2_4·a_7_16 + b_2_33·b_2_43·a_1_0 + b_2_34·a_4_5·b_1_2 + b_2_34·b_2_42·a_1_0 + b_2_35·b_2_4·a_1_0 + b_2_36·a_1_0 + b_2_34·a_4_5·a_1_0 + b_2_3·c_8_26·b_1_23 + a_4_5·c_8_26·a_1_0
- b_8_25·b_5_12 + b_2_3·b_2_43·b_5_13 + b_2_3·b_2_43·b_5_11 + b_2_32·b_1_24·b_5_11
+ b_2_32·b_2_42·b_5_11 + b_2_33·b_1_27 + b_2_33·b_2_4·b_5_13 + b_2_34·b_1_25 + b_2_35·b_1_23 + a_4_5·b_1_24·b_5_11 + b_2_46·a_1_1 + b_2_3·b_2_42·a_7_16 + b_2_32·b_2_4·a_7_16 + b_2_32·b_2_44·a_1_0 + b_2_33·b_2_43·a_1_0 + b_2_34·a_4_5·b_1_2 + b_2_36·a_1_1 + b_2_44·a_4_5·a_1_0 + b_2_3·c_8_26·b_1_23
- b_8_25·b_5_13 + b_2_44·b_5_13 + b_2_3·b_2_43·b_5_11 + b_2_32·b_1_24·b_5_11
+ b_2_33·b_1_22·b_5_11 + b_2_33·b_1_27 + b_2_34·b_5_13 + b_2_34·b_5_11 + b_2_34·b_1_25 + b_2_35·b_1_23 + a_4_5·b_1_24·b_5_11 + b_2_3·b_2_42·a_7_16 + b_2_3·b_2_45·a_1_0 + b_2_32·a_4_5·b_5_11 + b_2_32·a_4_5·b_1_25 + b_2_32·b_2_44·a_1_0 + b_2_34·a_4_5·b_1_2 + b_2_36·a_1_1 + b_2_36·a_1_0 + b_2_3·c_8_26·b_1_23 + a_4_5·c_8_26·a_1_0
- a_7_162 + b_2_46·a_1_0·a_1_1
- b_8_25·a_7_16 + b_2_44·a_7_16 + b_2_3·b_2_43·a_7_16 + b_2_32·b_2_45·a_1_0
+ b_2_33·a_4_5·b_5_11 + b_2_33·a_4_5·b_1_25 + b_2_33·b_2_44·a_1_0 + b_2_34·a_4_5·b_1_23 + b_2_34·b_2_43·a_1_0 + b_2_35·a_4_5·b_1_2 + b_2_36·b_2_4·a_1_0 + b_2_45·a_4_5·a_1_0 + b_2_35·a_4_5·a_1_0 + b_2_3·a_4_5·c_8_26·b_1_2 + b_2_3·a_4_5·c_8_26·a_1_0
- b_8_252 + b_2_48 + b_2_33·b_1_25·b_5_11 + b_2_33·b_2_45
+ b_2_34·b_1_23·b_5_11 + b_2_34·b_1_28 + b_2_35·b_1_26 + b_2_35·b_2_43 + b_2_36·b_1_24 + b_2_36·b_2_42 + b_2_32·a_4_5·b_1_23·b_5_11 + b_2_32·b_2_44·a_4_5 + b_2_33·a_4_5·b_1_26 + b_2_34·b_2_42·a_4_5 + b_2_32·c_8_26·b_1_24
Data used for Benson′s test
- Benson′s completion test succeeded in degree 16.
- 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_26, a Duflot regular element of degree 8
- b_1_24 + b_2_42 + b_2_3·b_2_4 + b_2_32, an element of degree 4
- b_2_3, an element of degree 2
- The Raw Filter Degree Type of that HSOP is [-1, -1, 9, 11].
- The filter degree type of any filter regular HSOP is [-1, -2, -3, -3].
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
- b_1_2 → 0, an element of degree 1
- b_2_3 → 0, an element of degree 2
- b_2_4 → 0, an element of degree 2
- a_3_6 → 0, an element of degree 3
- a_4_5 → 0, an element of degree 4
- a_4_6 → 0, an element of degree 4
- b_5_11 → 0, an element of degree 5
- b_5_12 → 0, an element of degree 5
- b_5_13 → 0, an element of degree 5
- a_7_16 → 0, an element of degree 7
- b_8_25 → 0, an element of degree 8
- c_8_26 → 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
- b_1_2 → c_1_1, an element of degree 1
- b_2_3 → c_1_22 + c_1_1·c_1_2, an element of degree 2
- b_2_4 → 0, an element of degree 2
- a_3_6 → 0, an element of degree 3
- a_4_5 → 0, an element of degree 4
- a_4_6 → 0, an element of degree 4
- b_5_11 → c_1_02·c_1_13 + c_1_04·c_1_1, an element of degree 5
- b_5_12 → c_1_1·c_1_24 + c_1_13·c_1_22 + c_1_02·c_1_13 + c_1_04·c_1_1, an element of degree 5
- b_5_13 → c_1_02·c_1_13 + c_1_04·c_1_1, an element of degree 5
- a_7_16 → 0, an element of degree 7
- b_8_25 → c_1_02·c_1_14·c_1_22 + c_1_02·c_1_15·c_1_2 + c_1_04·c_1_12·c_1_22
+ c_1_04·c_1_13·c_1_2, an element of degree 8
- c_8_26 → c_1_28 + c_1_12·c_1_26 + c_1_13·c_1_25 + c_1_14·c_1_24 + c_1_15·c_1_23
+ c_1_16·c_1_22 + c_1_02·c_1_12·c_1_24 + c_1_02·c_1_15·c_1_2 + c_1_04·c_1_24 + c_1_04·c_1_13·c_1_2 + c_1_04·c_1_14 + 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
- b_1_2 → 0, an element of degree 1
- b_2_3 → c_1_22 + c_1_12, an element of degree 2
- b_2_4 → c_1_22, an element of degree 2
- a_3_6 → 0, an element of degree 3
- a_4_5 → 0, an element of degree 4
- a_4_6 → 0, an element of degree 4
- b_5_11 → c_1_12·c_1_23 + c_1_14·c_1_2, an element of degree 5
- b_5_12 → c_1_1·c_1_24 + c_1_12·c_1_23 + c_1_13·c_1_22 + c_1_14·c_1_2, an element of degree 5
- b_5_13 → c_1_1·c_1_24 + c_1_14·c_1_2, an element of degree 5
- a_7_16 → 0, an element of degree 7
- b_8_25 → c_1_13·c_1_25 + c_1_15·c_1_23 + c_1_16·c_1_22, an element of degree 8
- c_8_26 → c_1_28 + c_1_16·c_1_22 + 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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