Dear Forum Members,
this is an announcement of a database of decomposition matrices
of `bicyclic' extensions of finite simple groups.
For each simple group G of order less than 10^9 in the
Atlas of Finite Groups, the Atlas of Brauer Characters shows the
Brauer character tables for all primes dividing the order of G.
Also, for larger simple groups in the Atlas of Finite Groups,
Brauer character tables at least for some `bicyclic' extensions
and some prime divisors of the group order are known.
A database of both DVI and PostScript files with the known
decomposition matrices of these groups is now available at
Many people have been involved in the computations of Brauer character
tables and decomposition matrices, as is stated in Section 17 in the
Introduction to the Atlas of Brauer Characters;
the book lists also several publications about the results.
For further references, see
The character tables for which the decomposition matrices are contained
in the database are all available in the computer algebra system GAP,
see one of
The GAP system provides many functions for computations with
group characters and character tables.
Also this database has been created automatically
from the character table library of GAP.
If you have suggestions how this database can be improved then
feel free to send an e-mail message to