Small group number 250 of order 64

G is the group 64gp250

The Hall-Senior number of this group is 43.

G has 4 minimal generators, rank 4 and exponent 8. The centre has rank 3.

There are 2 conjugacy classes of maximal elementary abelian subgroups. Their ranks are: 4, 4.

This cohomology ring calculation is complete.

Ring structure | Completion information | Koszul information | Restriction information | Poincaré series


Ring structure

The cohomology ring has 5 generators:

There is one minimal relation:

This minimal generating set constitutes a Gröbner basis for the relations ideal.


Completion information

This cohomology ring was obtained from a calculation out to degree 12. The cohomology ring approximation is stable from degree 2 onwards, and Benson's tests detect stability from degree 4 onwards.

This cohomology ring has dimension 4 and depth 4. Here is a homogeneous system of parameters:

The first 4 terms h1, h2, h3, h4 form a regular sequence of maximum length.

The first 3 terms h1, h2, h3 form a complete Duflot regular sequence. That is, their restrictions to the greatest central elementary abelian subgroup form a regular sequence of maximal length.

Data for Benson's test:


Koszul information

A basis for R/(h1, h2, h3, h4) is as follows.


Restriction information