Small group number 3 of order 625

G is the group 625gp3

G has 2 minimal generators, rank 3 and exponent 25. The centre has rank 2.

The 6 maximal subgroups are: Ab(25,5) (5x), V125.

There is one conjugacy class of maximal elementary abelian subgroups. Each maximal elementary abelian has rank 3.

This cohomology ring calculation is complete.

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


Ring structure

The cohomology ring has 16 generators:

There are 90 minimal relations:

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

Essential ideal: There are 7 minimal generators:

Nilradical: There are 13 minimal generators:


Completion information

This cohomology ring was obtained from a calculation out to degree 20. The cohomology ring approximation is stable from degree 20 onwards, and Carlson's tests detect stability from degree 20 onwards.

This cohomology ring has dimension 3 and depth 2. Here is a homogeneous system of parameters:

The first 2 terms h1, h2 form a regular sequence of maximum length. The remaining term h3 is annihilated by the class y1.

The first 2 terms h1, h2 form a complete Duflot regular sequence. That is, their restrictions to the greatest central elementary abelian subgroup form a regular sequence of maximal length.

The ideal of essential classes is free of rank 7 as a module over the polynomial algebra on h1, h2. These free generators are:

The essential ideal squares to zero.


Koszul information

A basis for R/(h1, h2, h3) is as follows. Carlson's Koszul condition stipulates that this must be confined to degrees less than 14.

A basis for AnnR/(h1, h2)(h3) is as follows. Carlson's Koszul condition stipulates that this must be confined to degrees less than 12.


Restriction information

Restrictions to maximal subgroups

Restriction to maximal subgroup number 1, which is V125

Restriction to maximal subgroup number 2, which is 125gp2

Restriction to maximal subgroup number 3, which is 125gp2

Restriction to maximal subgroup number 4, which is 125gp2

Restriction to maximal subgroup number 5, which is 125gp2

Restriction to maximal subgroup number 6, which is 125gp2

Restrictions to maximal elementary abelian subgroups

Restriction to maximal elementary abelian number 1, which is V125

Restriction to the greatest central elementary abelian subgroup

Restriction to the greatest central elementary abelian, which is V25


Poincaré series

(1 + 2t + 2t2 + 2t3 + t4) / (1 - t2)2 (1 - t10)


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