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Exponents of Class Groups of Quadratic Function Fields over Finite Fields

Published online by Cambridge University Press:  20 November 2018

David A. Cardon  and
M. Ram Murty
David A. Cardon
Affiliation:
Department of Mathematics Brigham Young University Provo, Utah 84602 USA, email: cardon@math.byu.edu
M. Ram Murty
Affiliation:
Department of Mathematics and Statistics Queen’s University Kingston, Ontario K7L 3N6, email: murty@mast.queensu.ca
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Abstract

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We find a lower bound on the number of imaginary quadratic extensions of the function field ${{\mathbb{F}}_{q}}\left( T \right)$ whose class groups have an element of a fixed order.

More precisely, let $q\,\ge \,5$ be a power of an odd prime and let $g$ be a fixed positive integer $\ge \,3$. There are $\gg \,{{q}^{\ell \left( \frac{1}{2}+\frac{1}{g} \right)}}$ polynomials $D\,\in \,{{\mathbb{F}}_{q}}\left[ T \right]$ with $\deg \left( D \right)\,\le \,\ell $ such that the class groups of the quadratic extensions ${{\mathbb{F}}_{q}}\left( T,\,\sqrt{D} \right)$ have an element of order $g$.

Keywords

11R5811R29class numberquadratic function field
Type
Research Article
Information
Canadian Mathematical Bulletin , Volume 44 , Issue 4 , 01 December 2001 , pp. 398 - 407
Copyright
Copyright © Canadian Mathematical Society 2001

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