Let q be an odd integer >3 and let G q be the Hecke group associated to q. Let ({) be a prime ideal of Z[\* q ] and G(q, {) the principal congruence subgroup of G q associated to {. We give a formula for [G q : G(q, {)], the index of the principal congruence subgroup G(q, {) in G q . We also give fo
Subgroups of the elementary and Steinberg groups of congruence level I2
โ Scribed by Susan C. Geller; Charles A. Weibel
- Publisher
- Elsevier Science
- Year
- 1985
- Tongue
- English
- Weight
- 549 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0022-4049
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๐ SIMILAR VOLUMES
We construct a special class of noncongruence modular subgroups and curves, analogous in some ways to the usual congruence ones. The subgroups are obtained via the Burau representation, and the associated quotient curves have a natural moduli space interpretation. In fact, they are reduced Hurwitz s
Normalizers of 1 0 (m)+w 2 and 1 0 (m)+w 3 in PSL 2 (R) are determined. The determination of such normalizers enables us to determine the normalizers (in PSL 2 (R)) of the congruence subgroups G 0 4 (A) and G 0 6 (A) of the Hecke groups G 4 and G 6 .
From 1 and the structure of แ it is clear that Dแ is stable under G, and that G acts trivially on แrDแ. Thus y g g Dแ 4 ลฝ . for all g g G.