# p_group_cohomology: Modular cohomology rings of finite groups#

## Description#

Modular Cohomology Rings of Finite Groups

The package is located at http://users.fmi.uni-jena.de/cohomology/, that’s to say the tarball p_group_cohomology-x.y.tar.xz can be found there and the documentation of the package is provided at http://users.fmi.uni-jena.de/cohomology/documentation/

## License#

Copyright (C) 2018 Simon A. King <simon.king@uni-jena.de> Copyright (C) 2011 Simon A. King <simon.king@uni-jena.de> Copyright (C) 2009 Simon A. King <simon.king@nuigalway.ie> and

David J. Green <david.green@uni-jena.de>

Distributed under the terms of the GNU General Public License (GPL), version 2 or later (at your choice).

This code is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

The full text of the GPL is available at:

The package includes a data base of cohomology rings of the groups of order 64 and provides access to a data base of cohomology rings of the groups of order 128 and 243, located at

These data bases are distributed under the Creative Commons Attribution-Share Alike 3.0 License. The full text of this licence is available at

## SPKG Maintainers#

Simon A. King <simon.king@uni-jena.de>

## Upstream Contact#

Simon A. King <simon.king@uni-jena.de> David J. Green <david.green@uni-jena.de>

## Acknowledgements#

The development of the initial version of this SPKG was funded by the German Science Foundation, DFG project GR 1585/4.1, and was accomplished at the Friedrich Schiller University Jena.

Since version 1.0.1, the further work on this SPKG was funded by Marie Curie grant MTKD-CT-2006-042685 and was pursued at the National University of Ireland, Galway. Since Novermber 2010, it is moved back to Jena.

We thank William Stein for giving us access to various computers on which we could build test the SPKG and on which some huge computations could be completed, and acknowledge the support by National Science Foundation Grant No. DMS-0821725.

We thank Mathieu Dutour Sikirić for hints on how to use GAP more efficiently.

We owe Peter Symonds the idea of using the Poincaré series in a rather efficient completeness criterion.

We are greatful to John Palmieri for his help on making p_group_cohomology work with python-3.

## Dependencies#

The SharedMeatAxe needs to be installed, as a build time dependency.

This can be met by installing the meataxe spkg

## Testing#

Our package provides a very short test suite for David Green’s routines for the computation of minimal projective resolutions. The majority of this package’s tests is formed by doc tests in the Cython code. In fact, any class, method and function is covered by tests.

Note that internet access is required for these tests, as it is attempted to download cohomology rings from a public data base in the web.

The script `spkg-check`

calls `sage -t --force_lib`

on the files
in `pGroupCohomology`

.

## Documentation#

The documentation of this package is automatically built, if the environment variable SAGE_SPKG_INSTALL_DOCS is yes (do “export SAGE_SPKG_INSTALL_DOCS=yes” on the command line before installation). The documents are put into SAGE_ROOT/local/share/doc/p_group_cohomology/.

## Type#

optional

## Dependencies#

$(PYTHON)

cython: C-Extensions for Python, an optimizing static compiler

p_group_cohomology: Modular cohomology rings of finite groups

$(PYTHON_TOOLCHAIN)

gap: Groups, Algorithms, Programming - a system for computational discrete algebra

$(SAGERUNTIME)

ipywidgets: Interactive HTML widgets for Jupyter notebooks and the IPython kernel

## Version Information#

package-version.txt:

```
3.3.3.p1
```

install-requires.txt:

```
p_group_cohomology >=3.3
```

## Equivalent System Packages#

See https://repology.org/project/sagemath-p-group-cohomology/versions

However, these system packages will not be used for building Sage because using Python site-packages is not supported by the Sage distribution; see github issue #29023