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Mod-5-Cohomology of SL(3,4), a group of order 60480
| About the group | Ring generators | Ring relations | Completion information | Restriction maps |
General information on the group
- SL(3,4) is a group of order 60480.
- The group order factors as
26 · 33 · 5 · 7 . - The group is defined by Group([(2,3,5)(4,7,6)(8,11,17)(9,13,21)(10,15,25)(12,19,32)(14,23,39)(16,27,46)(18,30,51)(20,34,52)(22,37,55)(24,41,56)(26,44,50)(28,48,59)(29,45,47)(31,33,36)(35,54,63)(38,40,43)(42,57,61)(49,53,62),(1,2,4,8,12,20,35)(3,6,9,14,24,42,58)(5,7,10,16,28,49,60)(11,18,31,23,40,56,62)(13,22,38,27,47,59,63)(15,26,45,19,33,52,61)(17,29,50,46,37,48,57)(21,36,51,32,44,34,53)(25,43,55,39,30,41,54)]).
- It is non-abelian.
- It has 5-Rank 1.
- The centre of a Sylow 5-subgroup has rank 1.
- Its Sylow 5-subgroup has a unique conjugacy class of maximal elementary abelian subgroups, which is of rank 1.
Structure of the cohomology ring
This cohomology ring is isomorphic to the cohomology ring of a subgroup, namely H*(SmallGroup(30,2); GF(5)).General information
- The cohomology ring is of dimension 1 and depth 1.
- The depth coincides with the Duflot bound.
- The Poincaré series is
( − 1)·(1 − t + t2) ( − 1 + t) · (1 + t2) - The a-invariants are -∞,-1. They were obtained using the filter regular HSOP of the Hilbert-Poincaré test.
- The filter degree type of any filter regular HSOP is [-1, -1].
| About the group | Ring generators | Ring relations | Completion information | Restriction maps |
Ring generators
The cohomology ring has 2 minimal generators of maximal degree 4:
-
a_3_0 , a nilpotent element of degree 3 -
c_4_0 , a Duflot element of degree 4
| About the group | Ring generators | Ring relations | Completion information | Restriction maps |
Ring relations
There is one "obvious" relation:
Apart from that, there are no relations.
| About the group | Ring generators | Ring relations | Completion information | Restriction maps |
Data used for the Hilbert-Poincaré test
- We proved completion in degree 4 using the Hilbert-Poincaré criterion.
- 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_4_0 , an element of degree 4
- The above filter regular HSOP forms a Duflot regular sequence.
- The Raw Filter Degree Type of the filter regular HSOP is [-1, 3].
| About the group | Ring generators | Ring relations | Completion information | Restriction maps |
Restriction maps
Expressing the generators as elements of H*(SmallGroup(30,2); GF(5))
-
a_3_0 →a_3_0 -
c_4_0 →c_4_0
Restriction map to the greatest el. ab. subgp. in the centre of a Sylow subgroup, which is of rank 1
-
a_3_0 →c_2_0·a_1_0 , an element of degree 3 -
c_4_0 →c_2_02 , an element of degree 4
| About the group | Ring generators | Ring relations | Completion information | Restriction maps |
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Simon King Department of Mathematics and Computer Science Friedrich-Schiller-Universität Jena 07737 Jena GERMANY
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