id,summary,reporter,owner,description,type,status,priority,milestone,component,resolution,keywords,cc,merged,author,reviewer,upstream,work_issues,branch,commit,dependencies,stopgaps
19830,Classification of finite and affine Coxeter groups,stumpc5,,"The bug here is two-fold:
1. The roots for a {{{CoxeterGroup}}} are constructed as in Humphreys ""in the Coxeter sense, that all have the same norm"". Therefore it seems more natural to not at all introduce a type C and to follow Humphrey's classification of finite Coxeter groups given on page 32.
2. The current implementation of types B/C (which I suggest to remove and to only keep type B) is also broken:
* First Sage start
{{{
sage: W = CoxeterGroup(['B',4])
sage: W.coxeter_matrix().coxeter_type()
Coxeter type of ['B', 4]
sage: W = CoxeterGroup(['C',4])
sage: W.coxeter_matrix().coxeter_type()
Coxeter type of ['B', 4]
}}}
* Second Sage start
{{{
sage: W = CoxeterGroup(['C',4])
sage: W.coxeter_matrix().coxeter_type()
Coxeter type of ['C', 4]
sage: W = CoxeterGroup(['B',4])
sage: W.coxeter_matrix().coxeter_type()
Coxeter type of ['C', 4]
}}}",defect,new,major,sage-7.1,combinatorics,,"coxeter system, root system",tscrim chapoton nthiery darij,,Travis Scrimshaw,,N/A,,public/combinat/fix_coxeter_type_relabelling-19830,d86d0abf581635109f147bc3b75c7efb0d819899,,