Simon King
David J. Green
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Singular
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Cohomology of group number 516 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 4.
- Its center has rank 2.
- It has a unique conjugacy class of maximal elementary abelian subgroups, which is of rank 4.
Structure of the cohomology ring
General information
- The cohomology ring is of dimension 4 and depth 2.
- The depth coincides with the Duflot bound.
- The Poincaré series is
t6 − t5 + 3·t4 − 3·t3 + 3·t2 − t + 1 |
| (t − 1)4 · (t2 + 1) · (t4 + 1) |
- The a-invariants are -∞,-∞,-4,-4,-4. They were obtained using the filter regular HSOP of the Benson test.
Ring generators
The cohomology ring has 18 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
- a_2_3, a nilpotent element of degree 2
- a_2_4, a nilpotent element of degree 2
- b_2_5, an element of degree 2
- b_2_6, an element of degree 2
- c_2_7, a Duflot regular element of degree 2
- a_3_10, a nilpotent element of degree 3
- a_3_15, a nilpotent element of degree 3
- a_5_37, a nilpotent element of degree 5
- b_5_40, an element of degree 5
- b_5_41, an element of degree 5
- a_6_57, a nilpotent element of degree 6
- a_6_48, a nilpotent element of degree 6
- b_6_60, an element of degree 6
- a_7_71, a nilpotent element of degree 7
- c_8_124, a Duflot regular element of degree 8
Ring relations
There are 103 minimal relations of maximal degree 14:
- a_1_02
- a_1_0·a_1_1
- a_1_0·b_1_2
- a_2_3·a_1_0
- a_2_3·b_1_2 + a_2_4·a_1_1
- a_2_4·a_1_0
- b_2_5·a_1_0
- b_2_6·a_1_0 + a_1_13
- a_2_32 + a_2_3·a_1_12
- a_1_12·b_1_22 + a_2_4·a_1_1·b_1_2 + a_2_42
- a_2_3·a_2_4 + a_2_4·a_1_12
- b_2_6·b_1_22 + b_2_52 + b_2_5·a_1_1·b_1_2 + c_2_7·a_1_12
- b_1_2·a_3_10 + a_2_4·b_2_5
- a_2_3·b_2_5 + a_1_1·a_3_10
- a_1_0·a_3_10
- b_1_2·a_3_15 + a_2_4·b_2_6 + b_2_5·a_1_12
- a_2_3·b_2_6 + a_1_1·a_3_15
- a_1_0·a_3_15 + a_2_32
- b_2_6·a_1_13
- b_2_5·a_3_10 + a_2_4·b_2_6·b_1_2 + a_2_4·b_2_5·a_1_1 + a_2_3·c_2_7·a_1_1
- b_2_5·a_1_12·b_1_2 + a_2_4·a_3_10 + a_2_4·b_2_5·a_1_1
- a_2_3·a_3_10 + a_1_12·a_3_10
- b_2_6·a_3_10 + b_2_5·a_3_15 + b_2_6·a_1_12·b_1_2
- b_2_6·a_1_12·b_1_2 + a_2_4·a_3_15 + a_2_4·b_2_6·a_1_1 + a_2_3·a_3_10
- a_2_3·a_3_15 + a_1_12·a_3_15
- a_3_102 + a_2_42·b_2_6 + a_2_4·b_2_5·a_1_12 + a_2_3·c_2_7·a_1_12
- a_3_10·a_3_15 + b_2_5·a_1_1·a_3_15 + b_2_5·b_2_6·a_1_12 + a_2_4·b_2_6·a_1_12
- a_3_152 + b_2_6·a_1_1·a_3_15 + b_2_62·a_1_12 + a_1_13·a_3_15
- b_1_2·a_5_37 + b_2_5·b_2_6·a_1_12
- a_1_1·a_5_37
- a_1_0·a_5_37 + a_1_13·a_3_15
- a_1_0·b_5_40 + a_1_13·a_3_15
- b_1_2·b_5_40 + b_2_5·b_2_62 + a_1_1·b_5_41
- a_1_0·b_5_41
- b_2_5·a_5_37 + a_2_4·b_2_6·a_3_15 + a_2_4·b_2_62·a_1_1 + b_2_5·a_1_12·a_3_15
- a_2_3·a_5_37
- a_2_4·a_5_37 + b_2_5·a_1_12·a_3_15
- b_2_6·a_5_37 + a_1_12·b_5_40
- b_2_5·b_2_6·a_3_15 + a_2_4·b_5_40 + a_2_3·b_5_41 + a_2_4·b_2_6·a_3_15
+ a_2_4·b_2_62·a_1_1 + b_2_5·a_1_12·a_3_15
- a_6_57·b_1_2 + a_2_4·b_5_40 + a_2_4·b_2_6·a_3_15
- a_2_3·b_5_40 + a_6_57·a_1_1 + b_2_6·a_1_12·a_3_15
- a_6_57·a_1_0
- a_1_1·b_1_2·b_5_41 + a_6_48·b_1_2 + b_2_52·b_2_6·a_1_1 + a_2_4·b_5_41
+ a_2_4·b_2_5·b_2_6·a_1_1
- b_2_5·b_2_6·a_3_15 + a_2_4·b_5_40 + a_1_12·b_5_41 + a_6_48·a_1_1 + b_2_5·a_1_12·a_3_15
- a_6_48·a_1_0
- b_6_60·b_1_2 + b_2_5·b_5_41 + b_2_52·b_2_6·a_1_1 + a_2_4·b_5_41 + a_2_4·b_2_5·a_3_15
+ a_2_42·b_2_6·a_1_1 + b_2_62·c_2_7·a_1_1
- b_2_63·b_1_2 + b_2_5·b_5_40 + b_6_60·a_1_1 + b_2_5·b_2_6·a_3_15 + b_2_5·b_2_62·a_1_1
+ a_2_4·b_5_40 + b_2_5·a_1_12·a_3_15
- b_6_60·a_1_0
- a_3_10·a_5_37 + a_2_4·b_2_62·a_1_12
- a_3_15·b_5_40 + b_2_6·a_6_57 + a_3_15·a_5_37 + b_2_62·a_1_1·a_3_15
- a_3_15·a_5_37 + a_2_3·a_6_57
- b_2_5·b_2_62·a_1_12 + a_2_4·a_1_1·b_5_40 + a_2_4·a_6_57
- a_3_15·a_5_37 + a_6_57·a_1_12
- a_3_10·b_5_41 + b_2_5·a_1_1·b_5_41 + b_2_5·a_6_48 + b_2_5·b_2_62·a_1_1·b_1_2
+ a_2_42·b_2_62 + a_2_4·b_2_5·b_2_6·a_1_12 + c_2_7·a_1_13·a_3_15
- a_3_15·b_5_41 + a_3_10·b_5_40 + b_2_6·a_1_1·b_5_41 + b_2_6·a_6_48 + b_2_5·a_1_1·b_5_40
+ b_2_5·a_6_57 + b_2_5·b_2_62·a_1_12 + a_2_4·b_2_62·a_1_12
- a_2_3·a_6_48 + a_2_4·b_2_62·a_1_12
- a_6_48·a_1_1·b_1_2 + a_2_4·a_1_1·b_5_41 + a_2_4·a_6_48 + a_2_42·b_2_62
+ a_2_4·b_2_5·b_2_6·a_1_12
- a_3_10·b_5_40 + b_2_5·a_6_57 + b_2_5·b_2_62·a_1_12 + a_2_4·a_1_1·b_5_40
+ a_6_48·a_1_12 + a_2_4·b_2_62·a_1_12
- b_2_6·b_1_2·b_5_41 + b_2_5·b_6_60 + a_3_10·b_5_41 + b_2_5·a_1_1·b_5_41
+ b_2_5·b_2_62·a_1_1·b_1_2 + a_2_4·b_2_62·a_1_1·b_1_2 + a_2_4·b_2_5·b_2_6·a_1_12 + c_2_7·a_1_1·b_5_40 + c_2_7·a_1_13·a_3_15
- a_3_10·b_5_40 + a_2_4·b_2_63 + a_2_3·b_6_60 + a_2_4·a_1_1·b_5_40
+ a_2_4·b_2_62·a_1_12
- a_3_10·b_5_41 + a_2_4·b_6_60 + a_6_48·a_1_1·b_1_2 + a_2_42·b_2_62
+ b_2_6·c_2_7·a_1_1·a_3_15 + c_2_7·a_1_13·a_3_15
- a_3_10·b_5_41 + b_1_2·a_7_71 + b_2_5·a_1_1·b_5_41 + b_2_5·b_2_62·a_1_1·b_1_2
+ a_6_48·a_1_1·b_1_2 + a_2_4·a_1_1·b_5_41 + a_2_4·b_2_62·a_1_1·b_1_2 + a_2_42·b_2_62 + a_2_4·b_2_5·b_2_6·a_1_12 + b_2_6·c_2_7·a_1_1·a_3_15 + b_2_62·c_2_7·a_1_12 + c_2_7·a_1_13·a_3_15
- a_3_10·b_5_40 + a_2_4·b_2_63 + a_1_1·a_7_71 + b_6_60·a_1_12 + b_2_5·b_2_62·a_1_12
+ a_2_4·a_1_1·b_5_40
- a_1_0·a_7_71
- a_6_57·a_3_15 + b_2_6·a_1_12·b_5_40 + b_2_6·a_6_57·a_1_1
- a_6_48·a_3_15 + a_6_57·a_3_10 + b_2_6·a_1_12·b_5_41 + a_2_4·b_2_62·a_3_15
+ a_2_4·b_2_63·a_1_1
- a_6_48·a_3_10 + b_2_5·a_6_48·a_1_1 + a_2_4·b_6_60·a_1_1 + a_2_42·b_5_40
+ b_2_6·c_2_7·a_1_12·a_3_15
- b_6_60·a_3_10 + a_2_4·b_2_6·b_5_41 + a_6_48·a_3_10 + a_2_42·b_2_62·a_1_1
+ c_2_7·a_6_57·a_1_1 + b_2_6·c_2_7·a_1_12·a_3_15
- b_2_5·a_7_71 + b_2_5·b_6_60·a_1_1 + b_2_52·b_2_62·a_1_1 + a_2_4·b_2_6·b_5_41
+ a_6_48·a_3_10 + a_2_42·b_5_40 + a_2_4·a_1_12·b_5_41 + a_2_42·b_2_62·a_1_1 + c_2_7·a_6_57·a_1_1 + b_2_6·c_2_7·a_1_12·a_3_15
- b_6_60·a_3_15 + b_2_6·a_7_71 + b_2_6·b_6_60·a_1_1 + b_2_5·b_2_63·a_1_1 + a_6_57·a_3_10
+ b_2_6·a_1_12·b_5_41 + a_2_4·a_6_57·a_1_1
- a_2_3·a_7_71 + a_2_4·a_6_57·a_1_1
- a_6_48·a_3_10 + a_2_4·a_7_71 + a_2_4·a_1_12·b_5_41
- a_6_57·a_3_10 + a_2_4·b_2_62·a_3_15 + a_1_12·a_7_71
- a_5_372
- a_5_37·b_5_40 + b_2_64·a_1_12
- a_5_37·b_5_41 + b_2_6·b_6_60·a_1_12 + b_2_6·a_6_48·a_1_12
- a_3_10·a_7_71 + a_2_4·b_2_6·a_6_48 + a_2_4·b_6_60·a_1_12 + a_2_42·a_1_1·b_5_40
- a_5_37·b_5_41 + a_3_15·a_7_71 + a_2_4·b_2_6·a_1_1·b_5_40 + b_2_6·a_6_48·a_1_12
- b_5_412 + b_2_5·b_2_6·b_6_60 + b_2_52·b_2_63 + b_2_5·b_2_6·a_6_48
+ b_2_52·a_1_1·b_5_40 + a_2_4·b_2_5·a_1_1·b_5_40 + a_2_42·b_2_63 + a_2_4·b_6_60·a_1_12 + a_2_42·a_1_1·b_5_40 + c_8_124·b_1_22 + b_2_64·c_2_7 + b_2_6·c_2_7·a_1_1·b_5_40 + b_2_63·c_2_7·a_1_12
- b_5_40·b_5_41 + b_2_62·b_6_60 + a_5_37·b_5_41 + b_2_62·a_6_48
+ b_2_5·b_2_6·a_1_1·b_5_40 + c_8_124·a_1_1·b_1_2
- b_5_402 + b_2_65 + b_2_62·a_1_1·b_5_40 + b_2_64·a_1_12 + c_8_124·a_1_12
- a_6_57·a_5_37 + b_2_63·a_1_12·a_3_15
- b_6_60·a_5_37 + a_6_48·a_5_37 + b_2_62·a_1_12·b_5_41
- a_6_48·a_5_37 + b_2_6·a_1_12·a_7_71
- a_6_48·b_5_40 + a_6_57·b_5_41 + b_2_62·b_6_60·a_1_1 + b_2_5·b_2_64·a_1_1
+ b_2_62·a_1_12·b_5_41 + a_2_4·b_2_63·a_3_15 + a_2_4·b_2_6·a_6_57·a_1_1 + c_8_124·a_1_12·b_1_2
- b_6_60·b_5_41 + b_2_5·b_2_62·b_5_41 + b_2_52·b_2_6·b_5_40 + a_6_48·b_5_41
+ a_2_4·b_2_6·a_7_71 + a_2_4·b_2_5·b_2_63·a_1_1 + a_2_4·b_2_6·a_1_12·b_5_41 + b_2_62·c_2_7·b_5_40 + b_2_5·c_8_124·b_1_2 + c_8_124·a_1_1·b_1_22 + b_2_64·c_2_7·a_1_1 + b_2_6·c_2_7·a_1_12·b_5_40
- b_6_60·b_5_40 + b_2_63·b_5_41 + a_6_57·b_5_41 + b_2_62·a_1_12·b_5_41
+ b_2_62·a_6_48·a_1_1 + a_2_4·b_2_63·a_3_15 + a_2_4·b_2_6·a_6_57·a_1_1 + b_2_5·c_8_124·a_1_1
- a_6_57·b_5_40 + b_2_64·a_3_15 + a_2_3·c_8_124·a_1_1
- a_6_48·b_5_41 + b_2_52·b_2_63·a_1_1 + a_2_4·b_2_62·b_5_41
+ a_2_4·b_2_5·b_2_6·b_5_40 + a_2_4·b_2_6·a_7_71 + a_2_4·b_2_5·b_2_63·a_1_1 + a_2_42·b_2_6·b_5_40 + a_2_4·b_2_6·a_1_12·b_5_41 + a_2_42·b_2_63·a_1_1 + c_8_124·a_1_1·b_1_22 + b_2_63·c_2_7·a_3_15 + b_2_64·c_2_7·a_1_1 + a_2_4·c_8_124·b_1_2 + b_2_6·c_2_7·a_1_12·b_5_40 + b_2_62·c_2_7·a_1_12·a_3_15
- a_6_57·b_5_41 + b_2_62·a_7_71 + b_2_62·b_6_60·a_1_1 + b_2_5·b_2_64·a_1_1
+ a_6_48·a_5_37 + b_2_62·a_1_12·b_5_41 + b_2_62·a_6_48·a_1_1 + a_2_4·b_2_64·a_1_1 + a_2_4·c_8_124·a_1_1
- a_6_57·a_6_48 + b_2_62·b_6_60·a_1_12 + a_2_4·b_2_62·a_1_1·b_5_40
+ a_2_4·b_2_64·a_1_12
- b_5_41·a_7_71 + a_6_48·b_6_60 + a_2_4·b_2_62·a_1_1·b_5_41
+ a_2_4·b_2_5·b_2_6·a_1_1·b_5_40 + a_2_42·b_2_64 + a_2_42·b_2_6·a_1_1·b_5_40 + b_2_64·c_2_7·a_1_12 + b_2_6·c_2_7·a_6_57·a_1_12
- a_5_37·a_7_71 + b_2_62·a_6_48·a_1_12
- b_6_602 + b_2_5·b_2_62·b_6_60 + b_2_52·b_2_64 + a_6_48·b_6_60
+ a_2_4·b_2_5·b_2_64 + a_6_482 + a_2_4·b_2_62·a_1_1·b_5_41 + a_2_4·b_2_62·a_6_48 + b_2_65·c_2_7 + b_2_52·c_8_124 + b_2_62·c_2_7·a_1_1·b_5_40 + b_2_62·c_2_7·a_6_57 + b_2_5·c_8_124·a_1_1·b_1_2 + a_2_4·b_2_5·c_8_124 + b_2_63·c_2_7·a_1_1·a_3_15
- a_6_572 + b_2_64·a_1_1·a_3_15 + b_2_65·a_1_12 + b_2_62·a_6_57·a_1_12
+ a_2_3·c_8_124·a_1_12
- a_6_482 + a_2_4·b_2_62·a_1_1·b_5_41 + a_2_42·b_2_64 + b_2_63·c_2_7·a_1_1·a_3_15
+ a_2_4·c_8_124·a_1_1·b_1_2
- b_6_602 + b_2_5·b_2_62·b_6_60 + b_2_52·b_2_64 + b_2_52·b_2_6·a_1_1·b_5_40
+ a_2_4·b_2_62·b_6_60 + a_2_4·b_2_5·b_2_6·a_1_1·b_5_40 + a_2_4·b_2_6·b_6_60·a_1_12 + a_2_42·b_2_6·a_1_1·b_5_40 + b_2_65·c_2_7 + b_2_52·c_8_124 + b_2_64·c_2_7·a_1_12 + a_2_42·c_8_124
- b_5_40·a_7_71 + a_6_57·b_6_60 + b_2_63·a_1_1·b_5_41 + b_2_5·b_2_62·a_1_1·b_5_40
+ a_6_57·a_6_48 + a_2_4·b_2_62·a_1_1·b_5_40 + a_2_4·b_2_62·a_6_57 + b_2_62·a_6_48·a_1_12 + b_2_5·c_8_124·a_1_12 + a_2_4·c_8_124·a_1_12
- b_5_40·a_7_71 + b_2_63·a_6_48 + a_2_4·b_2_62·a_1_1·b_5_40 + a_2_4·b_2_62·a_6_57
+ c_8_124·a_1_1·a_3_10 + b_2_5·c_8_124·a_1_12
- a_6_57·a_7_71 + b_2_63·a_1_12·b_5_41 + a_2_4·b_2_65·a_1_1 + b_2_62·a_1_12·a_7_71
- b_6_60·a_7_71 + b_2_52·b_2_64·a_1_1 + a_2_4·b_2_63·b_5_41
+ a_2_4·b_2_5·b_2_62·b_5_40 + a_6_48·a_7_71 + a_2_4·b_2_62·a_7_71 + a_2_4·b_2_62·b_6_60·a_1_1 + b_2_64·c_2_7·a_3_15 + b_2_65·c_2_7·a_1_1 + b_2_52·c_8_124·a_1_1 + a_2_4·b_2_6·c_8_124·b_1_2 + b_2_62·c_2_7·a_1_12·b_5_40 + b_2_63·c_2_7·a_1_12·a_3_15 + a_2_3·c_2_7·c_8_124·a_1_1
- a_6_48·a_7_71 + a_2_4·b_2_62·b_6_60·a_1_1 + a_2_42·b_2_62·b_5_40
+ a_2_42·b_2_64·a_1_1 + b_2_62·c_2_7·a_6_57·a_1_1 + a_2_4·b_2_5·c_8_124·a_1_1 + a_2_42·c_8_124·a_1_1
- a_7_712 + a_2_4·b_2_63·a_1_1·b_5_41 + a_2_42·b_2_65
+ a_2_4·b_2_62·b_6_60·a_1_12 + a_2_42·b_2_62·a_1_1·b_5_40 + b_2_64·c_2_7·a_1_1·a_3_15 + a_2_4·b_2_6·c_8_124·a_1_1·b_1_2 + b_2_62·c_2_7·a_6_57·a_1_12 + a_2_4·b_2_5·c_8_124·a_1_12 + a_2_3·c_2_7·c_8_124·a_1_12
Data used for Benson′s test
- Benson′s completion test succeeded in degree 14.
- 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_2_7, a Duflot regular element of degree 2
- c_8_124, a Duflot regular element of degree 8
- b_1_22 + b_2_6 + b_2_5, an element of degree 2
- b_1_22, an element of degree 2
- The Raw Filter Degree Type of that HSOP is [-1, -1, 6, 8, 10].
- The filter degree type of any filter regular HSOP is [-1, -2, -3, -4, -4].
Restriction maps
Restriction map to the greatest central el. ab. subgp., which is of rank 2
- 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
- a_2_3 → 0, an element of degree 2
- a_2_4 → 0, an element of degree 2
- b_2_5 → 0, an element of degree 2
- b_2_6 → 0, an element of degree 2
- c_2_7 → c_1_02, an element of degree 2
- a_3_10 → 0, an element of degree 3
- a_3_15 → 0, an element of degree 3
- a_5_37 → 0, an element of degree 5
- b_5_40 → 0, an element of degree 5
- b_5_41 → 0, an element of degree 5
- a_6_57 → 0, an element of degree 6
- a_6_48 → 0, an element of degree 6
- b_6_60 → 0, an element of degree 6
- a_7_71 → 0, an element of degree 7
- c_8_124 → c_1_18, an element of degree 8
Restriction map to a maximal el. ab. subgp. of rank 4
- a_1_0 → 0, an element of degree 1
- a_1_1 → 0, an element of degree 1
- b_1_2 → c_1_2, an element of degree 1
- a_2_3 → 0, an element of degree 2
- a_2_4 → 0, an element of degree 2
- b_2_5 → c_1_2·c_1_3, an element of degree 2
- b_2_6 → c_1_32, an element of degree 2
- c_2_7 → c_1_0·c_1_2 + c_1_02, an element of degree 2
- a_3_10 → 0, an element of degree 3
- a_3_15 → 0, an element of degree 3
- a_5_37 → 0, an element of degree 5
- b_5_40 → c_1_35, an element of degree 5
- b_5_41 → c_1_14·c_1_2 + c_1_0·c_1_34, an element of degree 5
- a_6_57 → 0, an element of degree 6
- a_6_48 → 0, an element of degree 6
- b_6_60 → c_1_14·c_1_2·c_1_3 + c_1_0·c_1_35, an element of degree 6
- a_7_71 → 0, an element of degree 7
- c_8_124 → c_1_38 + c_1_14·c_1_34 + c_1_18, an element of degree 8
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