ATLAS of Finite Group Representations
This ATLAS of Group Representations has been prepared by
Robert Wilson, Peter Walsh, Jonathan Tripp, Ibrahim Suleiman, Stephen Rogers,
Richard Parker, Simon Norton, Steve Linton and John Bray (in reverse
alphabetical order, because I'm fed up with always being last!).
This page has been accessed
times since 12th December 2000 - the last time the counter was reset after
a powercut (typical!).
(Between 2nd August 1999 and 12th December 2000 there were at least 15373 accesses.)
This website has been under continuous development for several years now,
growing from a few hundred representations in 1996 to well over two thousand
in 2000. Most have been constructed by the authors - these range from
trivial applications of the Meataxe to major research projects lasting weeks or months.
A few have been collected from other people - specific references
are given on the appropriate web pages.
Dates of last updates to the files can be ascertained
via the ftp access described below, using the command "ls -l".
As of December 2000, no development work is being done on this
Version 1. New material will appear in
Version 2 only.
For the moment, version 2 comes with a warning: USE AT YOUR OWN RISK!
It is incomplete, and has not been properly checked, and definitely contains
mistakes. Currently most of the sporadic, alternating, symplectic and
exceptional groups are implemented, while the linear, orthogonal and unitary
groups mostly are not. More details of the current status may be found
on this page.
Among the advantages of version 2 are:
- Systematic naming conventions for files
- A GAP4 interface, enabling automatic downloading of files from this website
- Most representations available in alternative formats: Meataxe ASCII,
Meataxe binary, and GAP.
- (Ultimately) more systematic (and automatic) checking of the information.
What's new - last updated 20th December 2000.
This ATLAS contains representations of many finite simple
groups and related groups such as covering groups and automorphism groups
of simple groups.
Other resources/links include:
- Some matrices are now available in GAP format. To obtain them,
first follow the links as normal, and then change "atlasreps" to "gap"
in the URL. A more user-friendly interface will be provided in
- An anonymous ftp server is now running to provide direct access to the
representations. This is intended for experts only, and it is NOT recommended
to run this within your browser.
ftp for.mat.bham.ac.uk and login as user atlasftp,
with password atlasftp.
Beware that there are several thousand files in the directory pub/reps, so
commands such as 'ls' are likely to be slow and unhelpful.
- Some (developing) procedures for checking
the information provided, and ensuring (limited) stability.
- Some information about the format
used for representations in this atlas.
- Some information about the
includes many decomposition matrices, etc.
20th December 2000.