MarriageTheoremのこと

_ arXiv:math 2012年11月20日分まで、IACR ePrint 2012/733まで確認済み

_ 気になった論文：Reflection subgroups of odd-angled Coxeter groups, Anna Felikson, Jessica Fintzen, Pavel Tumarkin, http://jp.arxiv.org/abs/1211.4194

We give a criterion for a finitely generated odd-angled Coxeter group to have a proper finite index subgroup generated by reflections. The answer is given in terms of the least prime divisors of the exponents of the Coxeter relations.