MeatAxe
2.4
Programs for working with modular representations

tcond [Options] [nt] [T MaxTime] [g NGen] Info M N Result
This program performs the final steps of the tensor condensation procedure. It calculates, for one or more elements a₁,a₂,…∊A, the action of e_{H}a_{i}e_{H} on the condensed tensor product (M⊗N)e_{H}.
As input, the program expects the action of a_{i} on M and N with respect to the same basis as the generators of the condensation subgroup H that were fed into precond before. The program also needs the semisimplicity basis calculated by pwkond, and the P and Q matrices calculated by precond.
If the generators are already given with repect to the semisimplicity basis, you can use the "n" option to tell tcond to skip the basis change.
The output are NGen matrices describing the action of e__{H}a_{i}e_{H} on (M⊗N)e_{H}. These matrices are written to Result.1, Result.2 ... If you use the "t" option, tcond also calculates the action of a_{i} on M and N with respect to the semisimplicity basis. This option cannot be used together with "n".
The following sequence of commands shows the complete procedure for condensing a tensor product. To make things more simple, we assume that M=N. The condensation subgroup shall be given by three generators in the files "sub.1", "sub.2", and "sub.3". The generators of the group shall be "g.1" and "g.2".
chop g 3 sub pwkond tb sub precond tp sub sub tcond g 2 tp g g result
After these commands are completed, the action of the condensed generators is in "result.1", "result.2", and "result.3".
The algorithm used by this program is described in [Wie94].