Subgroups of infinite index in the modular group
نویسندگان
چکیده
منابع مشابه
Finite Index Subgroups of the Modular Group and Their Modular Forms
Classically, congruence subgroups of the modular group, which can be described by congruence relations, play important roles in group theory and modular forms. In reality, the majority of finite index subgroups of the modular group are noncongruence. These groups as well as their modular forms are central players of this survey article. Differences between congruence and noncongruence subgroups...
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The elliptic elements of M, each with two conjugate complex fixed points, are precisely the conjugates of nontrivial powers of A and B. The parabolic elements, each with a single real fixed point, are precisely the conjugates of nontrivial powers of C = AB: z ~ z + 1. The remaining nontrivial elements of M are hyperbolic, each with two real fixed points. A subgroup S of M is torsionfree (and th...
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ژورنال
عنوان ژورنال: Glasgow Mathematical Journal
سال: 1978
ISSN: 0017-0895,1469-509X
DOI: 10.1017/s0017089500003347