Cohomology of group number 12 of order 625

About the group Ring generators Ring relations Completion information Restriction maps Back to groups of order 625

General information on the group

  • The group is also known as E125xC5, the Direct product E125 x C_5.
  • The group has 3 minimal generators and exponent 5.
  • It is non-abelian.
  • It has p-Rank 3.
  • Its center has rank 2.
  • It has 6 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 coincides with the Duflot bound.
  • The Poincaré series is
    ( − 1) · (t2  +  1) · (t6  +  t2  +  1)
    (t  −  1)3 · (t4  −  t3  +  t2  −  t  +  1) · (t4  +  t3  +  t2  +  t  +  1)

About the group Ring generators Ring relations Completion information Restriction maps Back to groups of order 625

Ring generators

The cohomology ring has 14 minimal generators of maximal degree 10:

  1. a_1_0, a nilpotent element of degree 1
  2. a_1_1, a nilpotent element of degree 1
  3. a_1_2, a nilpotent element of degree 1
  4. a_2_2, a nilpotent element of degree 2
  5. a_2_3, a nilpotent element of degree 2
  6. b_2_4, an element of degree 2
  7. b_2_5, an element of degree 2
  8. c_2_6, a Duflot regular element of degree 2
  9. a_3_11, a nilpotent element of degree 3
  10. a_3_12, a nilpotent element of degree 3
  11. a_7_43, a nilpotent element of degree 7
  12. b_8_46, an element of degree 8
  13. a_9_65, a nilpotent element of degree 9
  14. c_10_82, a Duflot regular element of degree 10

About the group Ring generators Ring relations Completion information Restriction maps Back to groups of order 625

Ring relations

There are 7 "obvious" relations:
   a_1_02, a_1_12, a_1_22, a_3_112, a_3_122, a_7_432, a_9_652

Apart from that, there are 44 minimal relations of maximal degree 17:

  1. a_1_0·a_1_1
  2. a_2_2·a_1_0
  3. a_2_3·a_1_1
  4. a_2_3·a_1_0 − a_2_2·a_1_1
  5. b_2_5·a_1_0 − b_2_4·a_1_1
  6. a_2_22
  7. a_2_2·a_2_3
  8. a_2_32
  9.  − 2·a_2_3·b_2_4 − a_2_2·b_2_5 + a_1_1·a_3_11
  10. a_2_2·b_2_4 + a_1_0·a_3_11
  11.  − a_2_3·b_2_5 + a_1_1·a_3_12
  12. a_2_3·b_2_4 + 2·a_2_2·b_2_5 + a_1_0·a_3_12
  13. a_2_2·a_3_11
  14.  − b_2_5·a_3_11 + b_2_4·a_3_12 + 2·b_2_4·b_2_5·a_1_1 + 2·b_2_42·a_1_1
  15.  − a_2_3·a_3_11 + a_2_2·a_3_12
  16. a_2_3·a_3_12
  17. a_1_1·a_7_43 − b_2_52·a_1_1·a_3_12 + 2·b_2_4·b_2_5·a_1_1·a_3_12
       − 2·b_2_42·a_1_1·a_3_12 + 2·b_2_42·a_1_0·a_3_12
  18. a_1_0·a_7_43 − b_2_4·b_2_5·a_1_1·a_3_12 + 2·b_2_42·a_1_1·a_3_12
       − 2·b_2_42·a_1_0·a_3_12 + 2·b_2_42·a_1_0·a_3_11
  19. b_2_5·a_7_43 − b_2_53·a_3_12 + 2·b_2_4·b_2_52·a_3_12 − 2·b_2_4·b_2_53·a_1_1
       − 2·b_2_42·b_2_5·a_3_12 + 2·b_2_42·b_2_52·a_1_1 + 2·b_2_43·a_3_12
       + 2·b_2_43·b_2_5·a_1_1 + b_2_44·a_1_1
  20. b_2_4·a_7_43 − b_2_4·b_2_52·a_3_12 + 2·b_2_4·b_2_53·a_1_1 + 2·b_2_42·b_2_5·a_3_12
       − 2·b_2_42·b_2_52·a_1_1 − 2·b_2_43·a_3_12 + 2·b_2_43·a_3_11 + 2·b_2_43·b_2_5·a_1_1
       − 2·b_2_44·a_1_1
  21. a_2_2·a_7_43
  22. a_2_3·a_7_43
  23. b_8_46·a_1_1 − b_2_4·b_2_53·a_1_1 + b_2_42·b_2_52·a_1_1 + 2·b_2_43·b_2_5·a_1_1
       − b_2_44·a_1_1
  24. b_8_46·a_1_0 − b_2_4·b_2_53·a_1_1 − b_2_42·b_2_52·a_1_1 + b_2_43·b_2_5·a_1_1
       + 2·b_2_44·a_1_1
  25. a_3_12·a_7_43 + 2·b_2_4·b_2_52·a_1_1·a_3_12 − 2·b_2_42·b_2_5·a_1_1·a_3_12
       − 2·b_2_43·a_1_1·a_3_12 − b_2_43·a_1_0·a_3_12
  26. a_3_11·a_7_43 + b_2_4·b_2_52·a_1_1·a_3_12 − b_2_42·b_2_5·a_1_1·a_3_12
       − 2·b_2_43·a_1_1·a_3_12 − 2·b_2_43·a_1_0·a_3_12
  27. b_2_5·b_8_46 − b_2_4·b_2_54 + b_2_42·b_2_53 + 2·b_2_43·b_2_52 − b_2_44·b_2_5
       − 2·b_2_53·a_1_1·a_3_12 + b_2_4·b_2_52·a_1_1·a_3_12 − b_2_42·b_2_5·a_1_1·a_3_12
       + 2·b_2_43·a_1_1·a_3_12 − 2·b_2_43·a_1_0·a_3_12
  28. b_2_4·b_8_46 − b_2_4·b_2_54 − b_2_42·b_2_53 + b_2_43·b_2_52 + 2·b_2_44·b_2_5
       − 2·b_2_4·b_2_52·a_1_1·a_3_12 + b_2_42·b_2_5·a_1_1·a_3_12 − b_2_43·a_1_1·a_3_12
       + 2·b_2_43·a_1_0·a_3_12 − 2·b_2_43·a_1_0·a_3_11
  29. a_2_2·b_8_46 + b_2_4·b_2_52·a_1_1·a_3_12 + b_2_42·b_2_5·a_1_1·a_3_12
       − b_2_43·a_1_1·a_3_12 − 2·b_2_43·a_1_0·a_3_12
  30. a_2_3·b_8_46 − b_2_4·b_2_52·a_1_1·a_3_12 + b_2_42·b_2_5·a_1_1·a_3_12
       + 2·b_2_43·a_1_1·a_3_12 − b_2_43·a_1_0·a_3_12
  31. a_1_1·a_9_65 − b_2_53·a_1_1·a_3_12 + b_2_4·b_2_52·a_1_1·a_3_12
       + b_2_42·b_2_5·a_1_1·a_3_12 + 2·b_2_43·a_1_1·a_3_12 + b_2_43·a_1_0·a_3_12
  32. a_1_0·a_9_65 + 2·b_2_4·b_2_52·a_1_1·a_3_12 + b_2_42·b_2_5·a_1_1·a_3_12
       + b_2_43·a_1_1·a_3_12 + 2·b_2_43·a_1_0·a_3_12 − 2·b_2_43·a_1_0·a_3_11
  33. b_8_46·a_3_12 − b_2_4·b_2_53·a_3_12 + b_2_42·b_2_52·a_3_12 + 2·b_2_43·b_2_5·a_3_12
       − b_2_44·a_3_12
  34. b_8_46·a_3_11 − b_2_4·b_2_53·a_3_12 − b_2_42·b_2_52·a_3_12 + b_2_42·b_2_53·a_1_1
       + b_2_43·b_2_5·a_3_12 + 2·b_2_44·a_3_12 + b_2_44·b_2_5·a_1_1 + 2·b_2_45·a_1_1
  35. b_2_5·a_9_65 − b_2_54·a_3_12 + b_2_4·b_2_53·a_3_12 + b_2_42·b_2_52·a_3_12
       + 2·b_2_42·b_2_53·a_1_1 + 2·b_2_43·b_2_5·a_3_12 + b_2_44·a_3_12
       − b_2_44·b_2_5·a_1_1 − b_2_45·a_1_1
  36. b_2_4·a_9_65 + 2·b_2_4·b_2_53·a_3_12 + b_2_42·b_2_52·a_3_12
       − 2·b_2_42·b_2_53·a_1_1 + b_2_43·b_2_5·a_3_12 + 2·b_2_43·b_2_52·a_1_1
       + 2·b_2_44·a_3_12 − 2·b_2_44·a_3_11 − 2·b_2_45·a_1_1
  37. a_2_2·a_9_65
  38. a_2_3·a_9_65
  39. a_3_12·a_9_65 − 2·b_2_42·b_2_52·a_1_1·a_3_12 + b_2_44·a_1_1·a_3_12
       + b_2_44·a_1_0·a_3_12
  40. a_3_11·a_9_65 − 2·b_2_42·b_2_52·a_1_1·a_3_12 + 2·b_2_43·b_2_5·a_1_1·a_3_12
       + b_2_44·a_1_1·a_3_12
  41. b_8_46·a_7_43 − b_2_44·b_2_52·a_3_12 − 2·b_2_45·b_2_5·a_3_12
       − 2·b_2_45·b_2_52·a_1_1 + 2·b_2_46·a_3_12 − b_2_47·a_1_1
  42. b_8_462 + 2·b_2_44·b_2_54 − b_2_45·b_2_53 + 2·b_2_46·b_2_52 + b_2_47·b_2_5
       − b_2_44·b_2_52·a_1_1·a_3_12 − b_2_45·b_2_5·a_1_1·a_3_12 + b_2_46·a_1_0·a_3_12
  43. a_7_43·a_9_65 + b_2_45·b_2_5·a_1_1·a_3_12 + 2·b_2_46·a_1_0·a_3_12
  44. b_8_46·a_9_65 − b_2_44·b_2_53·a_3_12 + 2·b_2_45·b_2_52·a_3_12
       − b_2_45·b_2_53·a_1_1 − 2·b_2_46·b_2_5·a_3_12 + 2·b_2_46·b_2_52·a_1_1
       + 2·b_2_47·a_3_12 − b_2_48·a_1_1

About the group Ring generators Ring relations Completion information Restriction maps Back to groups of order 625

Data used for Benson′s test

  • Benson′s completion test succeeded in degree 17.
  • 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:
    1. c_2_6, a Duflot regular element of degree 2
    2. c_10_82, a Duflot regular element of degree 10
    3. b_8_46 − b_2_54 − b_2_4·b_2_53 + b_2_42·b_2_52 + 2·b_2_43·b_2_5 − b_2_44, an element of degree 8
  • The Raw Filter Degree Type of that HSOP is [-1, -1, 7, 17].
  • The filter degree type of any filter regular HSOP is [-1, -2, -3, -3].

About the group Ring generators Ring relations Completion information Restriction maps Back to groups of order 625

Restriction maps

Restriction map to the greatest central el. ab. subgp., which is of rank 2

  1. a_1_0 → 0, an element of degree 1
  2. a_1_1 → 0, an element of degree 1
  3. a_1_2 → a_1_0, an element of degree 1
  4. a_2_2 → 0, an element of degree 2
  5. a_2_3 → 0, an element of degree 2
  6. b_2_4 → 0, an element of degree 2
  7. b_2_5 → 0, an element of degree 2
  8. c_2_6 → c_2_1, an element of degree 2
  9. a_3_11 → 0, an element of degree 3
  10. a_3_12 → 0, an element of degree 3
  11. a_7_43 → 0, an element of degree 7
  12. b_8_46 → 0, an element of degree 8
  13. a_9_65 → 0, an element of degree 9
  14. c_10_82 →  − c_2_25, an element of degree 10

Restriction map to a maximal el. ab. subgp. of rank 3

  1. a_1_0 → a_1_2, an element of degree 1
  2. a_1_1 → 0, an element of degree 1
  3. a_1_2 → a_1_0, an element of degree 1
  4. a_2_2 →  − a_1_1·a_1_2, an element of degree 2
  5. a_2_3 → 0, an element of degree 2
  6. b_2_4 → c_2_5, an element of degree 2
  7. b_2_5 → 0, an element of degree 2
  8. c_2_6 → c_2_3, an element of degree 2
  9. a_3_11 →  − c_2_5·a_1_1 + c_2_4·a_1_2, an element of degree 3
  10. a_3_12 → 0, an element of degree 3
  11. a_7_43 → 2·c_2_53·a_1_1 − 2·c_2_4·c_2_52·a_1_2, an element of degree 7
  12. b_8_46 → 2·c_2_53·a_1_1·a_1_2, an element of degree 8
  13. a_9_65 →  − 2·c_2_54·a_1_1 + 2·c_2_4·c_2_53·a_1_2, an element of degree 9
  14. c_10_82 → 2·c_2_54·a_1_1·a_1_2 + c_2_4·c_2_54 − c_2_45, an element of degree 10

Restriction map to a maximal el. ab. subgp. of rank 3

  1. a_1_0 → 0, an element of degree 1
  2. a_1_1 → a_1_2, an element of degree 1
  3. a_1_2 → a_1_0, an element of degree 1
  4. a_2_2 → 0, an element of degree 2
  5. a_2_3 → a_1_1·a_1_2, an element of degree 2
  6. b_2_4 → 0, an element of degree 2
  7. b_2_5 → c_2_5, an element of degree 2
  8. c_2_6 → c_2_3, an element of degree 2
  9. a_3_11 → 0, an element of degree 3
  10. a_3_12 →  − c_2_5·a_1_1 + c_2_4·a_1_2, an element of degree 3
  11. a_7_43 →  − c_2_53·a_1_1 + c_2_4·c_2_52·a_1_2, an element of degree 7
  12. b_8_46 → 2·c_2_53·a_1_1·a_1_2, an element of degree 8
  13. a_9_65 →  − c_2_54·a_1_1 + c_2_4·c_2_53·a_1_2, an element of degree 9
  14. c_10_82 → 2·c_2_54·a_1_1·a_1_2 + c_2_4·c_2_54 − c_2_45, an element of degree 10

Restriction map to a maximal el. ab. subgp. of rank 3

  1. a_1_0 → a_1_2, an element of degree 1
  2. a_1_1 → a_1_2, an element of degree 1
  3. a_1_2 → a_1_0, an element of degree 1
  4. a_2_2 →  − a_1_1·a_1_2, an element of degree 2
  5. a_2_3 → a_1_1·a_1_2, an element of degree 2
  6. b_2_4 → c_2_5, an element of degree 2
  7. b_2_5 → c_2_5, an element of degree 2
  8. c_2_6 → c_2_3, an element of degree 2
  9. a_3_11 → 2·c_2_5·a_1_2 − c_2_5·a_1_1 + c_2_4·a_1_2, an element of degree 3
  10. a_3_12 →  − 2·c_2_5·a_1_2 − c_2_5·a_1_1 + c_2_4·a_1_2, an element of degree 3
  11. a_7_43 →  − c_2_53·a_1_2 + c_2_53·a_1_1 − c_2_4·c_2_52·a_1_2, an element of degree 7
  12. b_8_46 → 2·c_2_53·a_1_1·a_1_2 − c_2_54, an element of degree 8
  13. a_9_65 →  − 2·c_2_54·a_1_2 − c_2_54·a_1_1 + c_2_4·c_2_53·a_1_2, an element of degree 9
  14. c_10_82 →  − c_2_54·a_1_1·a_1_2 + c_2_55 + c_2_4·c_2_54 − c_2_45, an element of degree 10

Restriction map to a maximal el. ab. subgp. of rank 3

  1. a_1_0 → 2·a_1_2, an element of degree 1
  2. a_1_1 → a_1_2, an element of degree 1
  3. a_1_2 → a_1_0, an element of degree 1
  4. a_2_2 →  − 2·a_1_1·a_1_2, an element of degree 2
  5. a_2_3 → a_1_1·a_1_2, an element of degree 2
  6. b_2_4 → 2·c_2_5, an element of degree 2
  7. b_2_5 → c_2_5, an element of degree 2
  8. c_2_6 → c_2_3, an element of degree 2
  9. a_3_11 →  − c_2_5·a_1_2 − 2·c_2_5·a_1_1 + 2·c_2_4·a_1_2, an element of degree 3
  10. a_3_12 → c_2_5·a_1_2 − c_2_5·a_1_1 + c_2_4·a_1_2, an element of degree 3
  11. a_7_43 →  − 2·c_2_53·a_1_2 + c_2_53·a_1_1 − c_2_4·c_2_52·a_1_2, an element of degree 7
  12. b_8_46 →  − 2·c_2_54, an element of degree 8
  13. a_9_65 →  − 2·c_2_54·a_1_2 + 2·c_2_54·a_1_1 − 2·c_2_4·c_2_53·a_1_2, an element of degree 9
  14. c_10_82 → c_2_54·a_1_1·a_1_2 − 2·c_2_55 + c_2_4·c_2_54 − c_2_45, an element of degree 10

Restriction map to a maximal el. ab. subgp. of rank 3

  1. a_1_0 → a_1_2, an element of degree 1
  2. a_1_1 → 2·a_1_2, an element of degree 1
  3. a_1_2 → a_1_0, an element of degree 1
  4. a_2_2 →  − a_1_1·a_1_2, an element of degree 2
  5. a_2_3 → 2·a_1_1·a_1_2, an element of degree 2
  6. b_2_4 → c_2_5, an element of degree 2
  7. b_2_5 → 2·c_2_5, an element of degree 2
  8. c_2_6 → c_2_3, an element of degree 2
  9. a_3_11 →  − c_2_5·a_1_2 − c_2_5·a_1_1 + c_2_4·a_1_2, an element of degree 3
  10. a_3_12 → c_2_5·a_1_2 − 2·c_2_5·a_1_1 + 2·c_2_4·a_1_2, an element of degree 3
  11. a_7_43 →  − c_2_53·a_1_2 − 2·c_2_53·a_1_1 + 2·c_2_4·c_2_52·a_1_2, an element of degree 7
  12. b_8_46 → c_2_53·a_1_1·a_1_2 + c_2_54, an element of degree 8
  13. a_9_65 →  − c_2_54·a_1_2 + c_2_54·a_1_1 − c_2_4·c_2_53·a_1_2, an element of degree 9
  14. c_10_82 → c_2_54·a_1_1·a_1_2 + c_2_4·c_2_54 − c_2_45, an element of degree 10

Restriction map to a maximal el. ab. subgp. of rank 3

  1. a_1_0 →  − a_1_2, an element of degree 1
  2. a_1_1 → a_1_2, an element of degree 1
  3. a_1_2 → a_1_0, an element of degree 1
  4. a_2_2 → a_1_1·a_1_2, an element of degree 2
  5. a_2_3 → a_1_1·a_1_2, an element of degree 2
  6. b_2_4 →  − c_2_5, an element of degree 2
  7. b_2_5 → c_2_5, an element of degree 2
  8. c_2_6 → c_2_3, an element of degree 2
  9. a_3_11 →  − 2·c_2_5·a_1_2 + c_2_5·a_1_1 − c_2_4·a_1_2, an element of degree 3
  10. a_3_12 → 2·c_2_5·a_1_2 − c_2_5·a_1_1 + c_2_4·a_1_2, an element of degree 3
  11. a_7_43 → c_2_53·a_1_2 − 2·c_2_53·a_1_1 + 2·c_2_4·c_2_52·a_1_2, an element of degree 7
  12. b_8_46 →  − 2·c_2_53·a_1_1·a_1_2 + c_2_54, an element of degree 8
  13. a_9_65 → 2·c_2_54·a_1_2 − 2·c_2_54·a_1_1 + 2·c_2_4·c_2_53·a_1_2, an element of degree 9
  14. c_10_82 → 2·c_2_54·a_1_1·a_1_2 − c_2_55 + c_2_4·c_2_54 − c_2_45, an element of degree 10

About the group Ring generators Ring relations Completion information Restriction maps Back to groups of order 625


Simon A. King David J. Green
Fakultät für Mathematik und Informatik Fakultät für Mathematik und Informatik
Friedrich-Schiller-Universität Jena Friedrich-Schiller-Universität Jena
Ernst-Abbe-Platz 2 Ernst-Abbe-Platz 2
D-07743 Jena D-07743 Jena
Germany Germany
E-mail: simon dot king at uni hyphen jena dot de
Tel: +49 (0)3641 9-46184
Fax: +49 (0)3641 9-46162
Office: Zi. 3524, Ernst-Abbe-Platz 2
E-mail: david dot green at uni hyphen jena dot de
Tel: +49 3641 9-46166
Fax: +49 3641 9-46162
Office: Zi 3512, Ernst-Abbe-Platz 2

Last change: 25.08.2009