G = D16 is Dihedral group of order 16
The Hall-Senior number of this group is 12.
G has 2 minimal generators, rank 2 and exponent 8. The centre has rank 1.
There are 2 conjugacy classes of maximal elementary abelian subgroups. Their ranks are: 2, 2.
This cohomology ring calculation is complete.
Ring structure | Completion information | Koszul information | Restriction information | Poincaré series
The cohomology ring has 3 generators:
There is one minimal relation:
This minimal generating set constitutes a Gröbner basis for the relations ideal.
This cohomology ring was obtained from a calculation out to degree 6. The cohomology ring approximation is stable from degree 2 onwards, and Benson's tests detect stability from degree 3 onwards.
This cohomology ring has dimension 2 and depth 2. Here is a homogeneous system of parameters:
The first 2 terms h1, h2 form a regular sequence of maximum length.
The first term h1 forms a complete Duflot regular sequence. That is, its restriction to the greatest central elementary abelian subgroup forms a regular sequence of maximal length.
Data for Benson's test:
A basis for R/(h1, h2) is as follows.
(1 + 2t + t2) / (1 - t2)2