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  Cohomology of group number 749 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 4 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 1.
   The depth coincides with the Duflot bound.
   The Poincaré series is    | ( − 2) · (t4  −  t3  +  1/2·t2  +  1/2) |  | 
 |  | (t  −  1)3 · (t4  +  1) | 
 The a-invariants are -∞,-3,-7,-3.  They were obtained using the first, the second power of the second, and the third filter regular parameter of the Benson test.
   
 
  Ring generators
The cohomology ring has 12 minimal generators of maximal degree 8:
 
   b_1_0, an element of degree 1
   b_1_1, an 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
   b_5_19, an element of degree 5
   b_5_20, an element of degree 5
   b_5_21, an element of degree 5
   b_8_43, an element of degree 8
   c_8_44, a Duflot regular element of degree 8
   
 
  Ring relations
There are 36 minimal relations of maximal degree 16:
 
   b_1_0·b_1_1
   b_1_0·b_1_2
   b_1_1·b_1_2
   a_2_3·b_1_1
   a_2_4·b_1_2 + a_2_3·b_1_2
   a_2_4·b_1_0
   b_2_6·b_1_1 + b_2_6·b_1_0 + b_2_5·b_1_2 + b_2_5·b_1_0
   a_2_32
   a_2_3·a_2_4
   a_2_42
   b_2_5·b_2_6·b_1_2 + b_2_5·b_2_6·b_1_0 + b_2_52·b_1_2 + b_2_52·b_1_0
   b_1_2·b_5_19 + a_2_4·b_2_5·b_2_6 + a_2_3·b_1_24
   b_1_1·b_5_19 + a_2_4·b_2_5·b_1_12 + a_2_4·b_2_5·b_2_6
   b_1_2·b_5_20 + a_2_4·b_2_5·b_2_6 + a_2_3·b_1_24 + a_2_3·b_2_6·b_1_22+ a_2_3·b_2_5·b_2_6 + a_2_3·b_2_52
 b_1_0·b_5_20 + b_1_0·b_5_19 + b_2_5·b_1_04 + b_2_52·b_1_02 + a_2_3·b_1_04+ a_2_3·b_2_5·b_2_6 + a_2_3·b_2_52
 b_1_0·b_5_21 + b_1_0·b_5_19 + b_2_52·b_1_02 + a_2_4·b_2_62 + a_2_4·b_2_5·b_2_6+ a_2_3·b_2_62 + a_2_3·b_2_5·b_1_02 + a_2_3·b_2_5·b_2_6
 b_1_1·b_5_21 + b_2_52·b_1_12 + a_2_4·b_2_62 + a_2_3·b_2_62 + a_2_3·b_2_5·b_2_6
   b_2_5·b_2_62·b_1_0 + b_2_52·b_2_6·b_1_0 + a_2_4·b_5_19
   b_2_5·b_2_62·b_1_0 + b_2_52·b_2_6·b_1_0 + a_2_3·b_5_20 + a_2_3·b_5_19+ a_2_3·b_2_5·b_1_03 + a_2_3·b_2_52·b_1_0
 b_2_6·b_5_20 + b_2_5·b_5_21 + b_2_5·b_2_62·b_1_0 + b_2_52·b_1_03+ b_2_52·b_2_6·b_1_0 + b_2_53·b_1_2 + b_2_53·b_1_1 + a_2_3·b_2_6·b_1_23
 + a_2_3·b_2_62·b_1_2 + a_2_3·b_2_5·b_1_03 + a_2_3·b_2_52·b_1_0
 a_2_4·b_5_21 + a_2_4·b_2_52·b_1_1 + a_2_3·b_5_21 + a_2_3·b_5_19 + a_2_3·b_2_52·b_1_0
   b_1_24·b_5_21 + b_8_43·b_1_2 + b_2_6·b_1_27 + b_2_63·b_1_23 + b_2_64·b_1_2+ b_2_54·b_1_2 + a_2_3·b_1_22·b_5_21 + a_2_3·b_1_27 + a_2_3·b_2_6·b_5_19
 + a_2_3·b_2_62·b_1_23 + a_2_3·b_2_5·b_5_20 + a_2_3·b_2_52·b_1_03
 + a_2_3·b_2_53·b_1_0
 b_1_04·b_5_19 + b_8_43·b_1_0 + b_2_64·b_1_0 + b_2_5·b_1_07 + b_2_53·b_1_03+ b_2_54·b_1_0 + a_2_3·b_1_02·b_5_19 + a_2_3·b_2_6·b_5_19 + a_2_3·b_2_5·b_5_20
 + a_2_3·b_2_5·b_1_05 + a_2_3·b_2_53·b_1_0
 b_1_14·b_5_20 + b_8_43·b_1_1 + b_2_64·b_1_0 + b_2_54·b_1_2 + b_2_54·b_1_1+ b_2_54·b_1_0 + a_2_4·b_1_12·b_5_20 + a_2_4·b_2_52·b_1_13 + a_2_3·b_2_6·b_5_19
 + a_2_3·b_2_5·b_5_20 + a_2_3·b_2_52·b_1_03 + a_2_3·b_2_53·b_1_0
 b_5_20·b_5_21 + b_5_192 + b_2_5·b_1_03·b_5_19 + b_2_52·b_1_1·b_5_20+ b_2_53·b_1_04 + b_2_54·b_1_02 + a_2_4·b_2_5·b_2_63 + a_2_4·b_2_52·b_2_62
 + a_2_4·b_2_53·b_2_6 + a_2_3·b_1_23·b_5_21 + a_2_3·b_1_03·b_5_19
 + a_2_3·b_2_6·b_1_2·b_5_21 + a_2_3·b_2_5·b_1_0·b_5_19 + a_2_3·b_2_5·b_2_63
 + a_2_3·b_2_53·b_1_02 + a_2_3·b_2_54
 b_5_212 + b_5_192 + b_2_6·b_1_23·b_5_21 + b_2_62·b_1_2·b_5_21 + b_2_62·b_1_26+ b_2_63·b_1_24 + b_2_64·b_1_22 + b_2_5·b_2_64 + b_2_53·b_2_62
 + b_2_54·b_1_12 + b_2_54·b_1_02 + a_2_4·b_2_64 + a_2_3·b_2_6·b_1_26
 + a_2_3·b_2_63·b_1_22 + a_2_3·b_2_64 + a_2_3·b_2_5·b_2_63 + c_8_44·b_1_22
 b_5_192 + b_8_43·b_1_02 + b_2_5·b_1_08 + b_2_52·b_1_0·b_5_19 + b_2_52·b_1_06+ b_2_52·b_2_63 + b_2_53·b_2_62 + a_2_4·b_2_53·b_2_6 + a_2_3·b_1_03·b_5_19
 + c_8_44·b_1_02
 b_5_202 + b_5_192 + b_8_43·b_1_12 + b_2_5·b_1_13·b_5_20 + b_2_52·b_1_1·b_5_20+ b_2_52·b_1_16 + b_2_52·b_1_06 + b_2_52·b_2_63 + b_2_54·b_1_02
 + b_2_54·b_2_6 + a_2_4·b_1_13·b_5_20 + a_2_4·b_2_5·b_1_16 + a_2_4·b_2_52·b_1_14
 + a_2_4·b_2_53·b_1_12 + a_2_4·b_2_53·b_2_6 + a_2_3·b_2_53·b_2_6 + a_2_3·b_2_54
 + c_8_44·b_1_12
 b_5_19·b_5_20 + b_5_192 + b_2_5·b_1_13·b_5_20 + b_2_5·b_8_43 + b_2_5·b_2_64+ b_2_52·b_1_0·b_5_19 + b_2_52·b_1_06 + b_2_53·b_2_62 + b_2_54·b_1_02
 + b_2_54·b_2_6 + b_2_55 + a_2_4·b_2_5·b_2_63 + a_2_4·b_2_53·b_1_12
 + a_2_4·b_2_53·b_2_6 + a_2_3·b_1_03·b_5_19 + a_2_3·b_2_5·b_1_0·b_5_19
 + a_2_3·b_2_5·b_2_63 + a_2_3·b_2_52·b_1_04 + a_2_3·b_2_53·b_1_02
 + a_2_3·b_2_54
 b_5_20·b_5_21 + b_5_19·b_5_21 + b_2_6·b_1_23·b_5_21 + b_2_6·b_8_43 + b_2_62·b_1_26+ b_2_64·b_1_22 + b_2_65 + b_2_5·b_2_64 + b_2_52·b_1_1·b_5_20
 + b_2_52·b_1_0·b_5_19 + b_2_52·b_1_06 + b_2_52·b_2_63 + b_2_53·b_1_04
 + b_2_54·b_2_6 + a_2_4·b_2_64 + a_2_4·b_2_53·b_1_12 + a_2_3·b_1_03·b_5_19
 + a_2_3·b_2_6·b_1_26 + a_2_3·b_2_63·b_1_22 + a_2_3·b_2_64
 + a_2_3·b_2_5·b_1_0·b_5_19 + a_2_3·b_2_5·b_2_63 + a_2_3·b_2_52·b_1_04
 + a_2_3·b_2_53·b_2_6 + a_2_3·b_2_54
 b_5_20·b_5_21 + b_5_192 + b_2_5·b_1_03·b_5_19 + b_2_52·b_1_1·b_5_20+ b_2_53·b_1_04 + b_2_54·b_1_02 + a_2_4·b_2_53·b_2_6 + a_2_3·b_8_43
 + a_2_3·b_2_6·b_1_2·b_5_21 + a_2_3·b_2_6·b_1_26 + a_2_3·b_2_63·b_1_22
 + a_2_3·b_2_64 + a_2_3·b_2_5·b_1_0·b_5_19 + a_2_3·b_2_5·b_1_06
 + a_2_3·b_2_5·b_2_63 + a_2_3·b_2_52·b_2_62 + a_2_3·b_2_53·b_2_6
 b_5_20·b_5_21 + b_5_192 + b_2_5·b_1_03·b_5_19 + b_2_52·b_1_1·b_5_20+ b_2_53·b_1_04 + b_2_54·b_1_02 + a_2_4·b_1_13·b_5_20 + a_2_4·b_8_43
 + a_2_4·b_2_64 + a_2_4·b_2_5·b_2_63 + a_2_4·b_2_54 + a_2_3·b_1_03·b_5_19
 + a_2_3·b_2_6·b_1_2·b_5_21 + a_2_3·b_2_6·b_1_26 + a_2_3·b_2_63·b_1_22
 + a_2_3·b_2_5·b_1_0·b_5_19 + a_2_3·b_2_53·b_1_02 + a_2_3·b_2_53·b_2_6
 + a_2_3·b_2_54
 b_8_43·b_5_21 + b_8_43·b_5_19 + b_2_62·b_1_29 + b_2_62·b_8_43·b_1_2+ b_2_63·b_1_22·b_5_21 + b_2_64·b_5_21 + b_2_64·b_5_19 + b_2_64·b_1_25
 + b_2_65·b_1_23 + b_2_66·b_1_2 + b_2_5·b_2_63·b_5_21 + b_2_52·b_8_43·b_1_1
 + b_2_52·b_8_43·b_1_0 + b_2_52·b_2_62·b_5_21 + b_2_52·b_2_62·b_5_19
 + b_2_53·b_2_6·b_5_19 + b_2_54·b_5_21 + b_2_54·b_5_19 + b_2_55·b_2_6·b_1_0
 + b_2_56·b_1_1 + b_2_56·b_1_0 + a_2_4·b_2_5·b_8_43·b_1_1 + a_2_4·b_2_55·b_1_1
 + a_2_3·b_2_6·b_8_43·b_1_2 + a_2_3·b_2_62·b_1_22·b_5_21 + a_2_3·b_2_62·b_1_27
 + a_2_3·b_2_63·b_1_25 + a_2_3·b_2_64·b_1_23 + a_2_3·b_2_65·b_1_2
 + a_2_3·b_2_5·b_8_43·b_1_0 + a_2_3·b_2_52·b_2_6·b_5_21 + a_2_3·b_2_53·b_5_20
 + a_2_3·b_2_54·b_1_03 + c_8_44·b_1_25 + a_2_3·c_8_44·b_1_23
 + a_2_3·b_2_5·c_8_44·b_1_2
 b_8_43·b_5_19 + b_8_43·b_1_05 + b_2_64·b_5_19 + b_2_5·b_1_011+ b_2_5·b_8_43·b_1_03 + b_2_5·b_2_63·b_5_19 + b_2_52·b_8_43·b_1_0
 + b_2_52·b_2_62·b_5_21 + b_2_53·b_1_02·b_5_19 + b_2_53·b_1_07
 + b_2_53·b_2_6·b_5_21 + b_2_53·b_2_6·b_5_19 + b_2_54·b_5_19 + b_2_54·b_1_05
 + b_2_55·b_1_03 + b_2_55·b_2_6·b_1_0 + b_2_56·b_1_0 + a_2_4·b_2_5·b_8_43·b_1_1
 + a_2_4·b_2_55·b_1_1 + a_2_3·b_8_43·b_1_23 + a_2_3·b_2_64·b_1_23
 + a_2_3·b_2_5·b_2_62·b_5_21 + a_2_3·b_2_52·b_1_02·b_5_19
 + a_2_3·b_2_52·b_2_6·b_5_19 + a_2_3·b_2_53·b_1_05 + a_2_3·b_2_54·b_1_03
 + a_2_3·b_2_55·b_1_0 + c_8_44·b_1_05 + a_2_3·c_8_44·b_1_03
 + a_2_3·b_2_5·c_8_44·b_1_2
 b_8_43·b_5_21 + b_8_43·b_5_20 + b_8_43·b_1_15 + b_2_62·b_1_29+ b_2_62·b_8_43·b_1_2 + b_2_63·b_1_22·b_5_21 + b_2_64·b_5_21 + b_2_64·b_1_25
 + b_2_65·b_1_23 + b_2_66·b_1_2 + b_2_5·b_8_43·b_1_13 + b_2_5·b_8_43·b_1_03
 + b_2_5·b_2_63·b_5_19 + b_2_52·b_1_19 + b_2_52·b_2_62·b_5_21
 + b_2_53·b_2_6·b_5_21 + b_2_53·b_2_6·b_5_19 + b_2_54·b_5_20 + b_2_55·b_1_13
 + b_2_55·b_1_03 + b_2_55·b_2_6·b_1_0 + b_2_56·b_1_1 + b_2_56·b_1_0
 + a_2_4·b_2_5·b_1_19 + a_2_4·b_2_52·b_1_12·b_5_20 + a_2_3·b_8_43·b_1_03
 + a_2_3·b_2_62·b_1_22·b_5_21 + a_2_3·b_2_62·b_1_27 + a_2_3·b_2_63·b_5_19
 + a_2_3·b_2_63·b_1_25 + a_2_3·b_2_65·b_1_2 + a_2_3·b_2_5·b_8_43·b_1_0
 + a_2_3·b_2_5·b_2_62·b_5_19 + a_2_3·b_2_52·b_2_6·b_5_21
 + a_2_3·b_2_52·b_2_6·b_5_19 + a_2_3·b_2_53·b_5_21 + a_2_3·b_2_53·b_5_20
 + c_8_44·b_1_25 + c_8_44·b_1_15 + a_2_4·c_8_44·b_1_13 + a_2_3·c_8_44·b_1_23
 b_8_43·b_1_18 + b_8_43·b_1_08 + b_8_432 + b_2_6·b_8_43·b_1_26+ b_2_62·b_1_212 + b_2_62·b_8_43·b_1_24 + b_2_68 + b_2_5·b_1_014
 + b_2_5·b_8_43·b_1_16 + b_2_52·b_1_112 + b_2_52·b_8_43·b_1_14
 + b_2_52·b_8_43·b_1_04 + b_2_52·b_2_66 + b_2_53·b_1_010 + b_2_53·b_2_65
 + b_2_55·b_1_16 + b_2_55·b_1_06 + b_2_55·b_2_63 + b_2_56·b_1_14
 + b_2_56·b_1_04 + b_2_56·b_2_62 + b_2_58 + a_2_4·b_8_43·b_1_16
 + a_2_4·b_2_5·b_1_112 + a_2_4·b_2_5·b_8_43·b_1_14 + a_2_4·b_2_52·b_1_110
 + a_2_4·b_2_52·b_8_43·b_1_12 + a_2_4·b_2_55·b_1_14 + a_2_4·b_2_56·b_1_12
 + a_2_3·b_8_43·b_1_06 + a_2_3·b_2_6·b_8_43·b_1_24 + a_2_3·b_2_62·b_8_43·b_1_22
 + a_2_3·b_2_63·b_1_28 + a_2_3·b_2_66·b_1_22 + a_2_3·b_2_5·b_1_012
 + a_2_3·b_2_52·b_8_43·b_1_02 + a_2_3·b_2_53·b_1_08 + a_2_3·b_2_54·b_1_06
 + a_2_3·b_2_55·b_1_04 + c_8_44·b_1_28 + c_8_44·b_1_18 + c_8_44·b_1_08
 
 
 
  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_44, a Duflot regular element of degree 8
      b_1_24 + b_1_14 + b_1_04 + b_2_62 + b_2_5·b_2_6 + b_2_52, an element of degree 4
      b_2_62·b_1_22 + b_2_5·b_2_62 + b_2_52·b_1_12 + b_2_52·b_1_02 + b_2_52·b_2_6, an element of degree 6
       The Raw Filter Degree Type of that HSOP is [-1, 5, 5, 15].
     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
  
       b_1_0 → 0, an element of degree 1
       b_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
       b_5_19 → 0, an element of degree 5
       b_5_20 → 0, an element of degree 5
       b_5_21 → 0, an element of degree 5
       b_8_43 → 0, an element of degree 8
       c_8_44 → c_1_08, an element of degree 8
       
    Restriction map to a maximal el. ab. subgp. of rank 3
  
       b_1_0 → c_1_1, an element of degree 1
       b_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 → c_1_22 + c_1_1·c_1_2, an element of degree 2
       b_2_6 → c_1_22 + c_1_1·c_1_2, an element of degree 2
       b_5_19 → c_1_13·c_1_22 + c_1_14·c_1_2 + c_1_02·c_1_13 + c_1_04·c_1_1, an element of degree 5
       b_5_20 → 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_21 → c_1_1·c_1_24 + c_1_14·c_1_2 + c_1_02·c_1_13 + c_1_04·c_1_1, an element of degree 5
       b_8_43 → 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_02·c_1_16 + c_1_04·c_1_14, an element of degree 8
 c_8_44 → c_1_16·c_1_22 + c_1_17·c_1_2 + c_1_02·c_1_12·c_1_24 + c_1_02·c_1_14·c_1_22+ c_1_02·c_1_16 + c_1_04·c_1_24 + c_1_04·c_1_12·c_1_22 + c_1_08, an element of degree 8
 
    Restriction map to a maximal el. ab. subgp. of rank 3
  
       b_1_0 → 0, an element of degree 1
       b_1_1 → c_1_1, 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 → c_1_22 + c_1_1·c_1_2, an element of degree 2
       b_2_6 → 0, an element of degree 2
       b_5_19 → 0, an element of degree 5
       b_5_20 → 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_21 → c_1_1·c_1_24 + c_1_13·c_1_22, an element of degree 5
       b_8_43 → c_1_28 + c_1_16·c_1_22 + c_1_02·c_1_16 + c_1_04·c_1_14, an element of degree 8
       c_8_44 → c_1_28 + c_1_12·c_1_26 + c_1_13·c_1_25 + c_1_15·c_1_23+ c_1_02·c_1_12·c_1_24 + c_1_02·c_1_15·c_1_2 + c_1_02·c_1_16
 + c_1_04·c_1_24 + c_1_04·c_1_13·c_1_2 + c_1_08, an element of degree 8
 
    Restriction map to a maximal el. ab. subgp. of rank 3
  
       b_1_0 → 0, an element of degree 1
       b_1_1 → 0, an element of degree 1
       b_1_2 → c_1_1, 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 → c_1_22 + c_1_1·c_1_2, an element of degree 2
       b_5_19 → 0, an element of degree 5
       b_5_20 → 0, an element of degree 5
       b_5_21 → 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_8_43 → 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_17·c_1_2 + c_1_02·c_1_16 + c_1_04·c_1_14, an element of degree 8
 c_8_44 → c_1_28 + 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
  
       b_1_0 → 0, an element of degree 1
       b_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 → c_1_22 + c_1_12, an element of degree 2
       b_2_6 → c_1_12, an element of degree 2
       b_5_19 → c_1_12·c_1_23 + c_1_14·c_1_2, an element of degree 5
       b_5_20 → 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_21 → c_1_13·c_1_22 + c_1_14·c_1_2, an element of degree 5
       b_8_43 → c_1_28 + c_1_12·c_1_26 + 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_44 → c_1_28 + c_1_12·c_1_26 + c_1_13·c_1_25 + 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_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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