Symplectic C7

[TristanPfersdorff]

Exactly what you would expect. Unfortunately, there are not many test examples for these groups, since the requirements on m, t and q are quite strict.

Checklist for the reviewer

General

• [ ] All functions have unit tests

Functions constructing generators of maximal subgroups

• [ ] The code which computes and then stores the sizes is correct. To do this one confers to the tables referenced by the code. Tests for the group size should use RECOG.TestGroup from the recog package.
• [ ] The test suite checks whether all constructed generators are sensible. That is it tests the generators'
  • [ ] determinants (and if applicable also the spinor norms are correct), and
  • [ ] compatibility with the correct form,
  • [ ] DefaultFieldOfMatrixGroup returns the correct field.

Functions assembling the list of all maximal subgroups of a certain group

• [ ] The code agrees with the tables in section 8.2 of the book "The Maximal Subgroups of the Low-dimensional Finite Classical Groups".

The reviewer doesn't need to compare our results to magma's results. That's the job of the person implementing the code.

[TristanPfersdorff]

Hmm, RECOG-weirdness again. Will see if I can get the random seeds for reproducing it when I have the time.

Edit: Here we go, just start gap and copy-paste this into gap repro_S_C7_2_5_3.txt

The error message "Error, the recognition described by this recognition node has failed!" seems to suggest that this is just a sad case where RECOG is not powerful enough to recognize this group rather than some crazy internal malfunction. Nevertheless, I'm leaving this here for someone who knows RECOG better than I do. Just keep in mind that this is a pretty large group, as it is a C7-subgroup of Sp(32, 3). There are not a lot of smaller test examples though.

[codecov[bot]]

Codecov Report

Merging #84 (341cbec) into main (d698214) will decrease coverage by 0.30%. The diff coverage is 65.51%.

@@            Coverage Diff             @@
##             main      #84      +/-   ##
==========================================
- Coverage   92.36%   92.05%   -0.31%     
==========================================
  Files          14       14              
  Lines        2514     2543      +29     
==========================================
+ Hits         2322     2341      +19     
- Misses        192      202      +10     

Impacted Files	Coverage Δ
gap/ClassicalMaximals.gi	82.86% <9.09%> (-1.38%)	:arrow_down:
gap/TensorInducedMatrixGroups.gi	96.82% <100.00%> (+0.52%)	:arrow_up:

[fingolfin]

Thanks. I added a fully selfcontained reproducer for the recog bug at https://github.com/gap-packages/recog/issues/302#issuecomment-979994365