2006 / December Volume 1 No.4
A class of congruence subgroups of Hecke group $H( \lambda_{5}) $
| Published Date |
2006 / December
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| Title | A class of congruence subgroups of Hecke group $H( \lambda_{5}) $ |
| Author | |
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| Pagination | 549-556 |
| Abstract | In [2], it is shown that, for some Hecke groups, unlike the modular group, two denitions of the principal congruence subgroups
may not coincide and congruence and principal congruence subgroups of two important Hecke groups $H(\sqrt{m})$, for $m = 2$ or $3$, are classied and the quotients of $H(\sqrt{m})$ with these normal subgroups are given. Here we obtain a classication of the congruence
subgroups obtained as the kernel of reduction homomorphism for another important Hecke group $H(\lambda_5)$ and also obtain the quotient groups. Finally the indices and abstract group structure of all these subgroups are determined.
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| AMS Subject Classification |
20H05, 11F06, 11F41, 11F46
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| Received |
2005-11-10
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