A constructive method for the cycloidal normal free subgroups of finite index of Hecke groups $H(\sqrt{2})$ and $H(\sqrt{3})$
by Setenay Doğan   Musa Demirci   Osman Bizim   İsmail Naci Cangül  

Vol. 1 No. 3 (2006) P.429~P.436

ABSTRACT

Cycloidal subgrups of the modular group are studied in [8]. Here cycloidal free normal subgroups of Hecke groups are considered. It is found that when $q \equiv 2$ (mod 4), $H(\lambda_q)$ has no such subgroups. In all other cases the signatures of these subgroups are constructed by means of $q$-gons and their signatures are given.

KEYWORDS
Cycloidal subgroups, Hecke groups, permutation method

MATHEMATICAL SUBJECT CLASSIFICATION 2010
Primary: 20H05, 11F06, 11F41, 11F46

MILESTONES

Received: 2005-11-10
Revised :
Accepted:

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