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On a unit group generated by special values
of Siegel modular functions

Authors: T. Fukuda and K. Komatsu
Journal: Math. Comp. 69 (2000), 1207-1212
MSC (1991): Primary 11G15, 11R27, 11Y40
Published electronically: February 19, 1999
MathSciNet review: 1651753
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Abstract: There has been important progress in constructing units and $S$-units associated to curves of genus 2 or 3. These approaches are based mainly on the consideration of properties of Jacobian varieties associated to hyperelliptic curves of genus 2 or 3. In this paper, we construct a unit group of the ray class field $k_6$ of $\mathbb{Q}(\exp(2\pi i/5))$ modulo 6 with full rank by special values of Siegel modular functions and circular units. We note that $k_6=\mathbb{Q}(\exp(2\pi i/15),\,\sqrt[5]{-24}\,)$. Our construction of units is number theoretic, and closely based on Shimura's work describing explicitly the Galois actions on the special values of theta functions.

References [Enhancements On Off] (What's this?)

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Additional Information

T. Fukuda
Affiliation: Department of Mathematics, College of Industrial Technology, Nihon University, 2-11-1 Shin-ei, Narashino, Chiba, Japan

K. Komatsu
Affiliation: Department of Information and Computer Science, School of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169, Japan

Keywords: Siegel modular functions, unit groups, computation
Received by editor(s): October 16, 1997
Received by editor(s) in revised form: August 14, 1998
Published electronically: February 19, 1999
Article copyright: © Copyright 2000 American Mathematical Society

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