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arXiv · 0706.2112

Kloosterman sums, elliptic curves, and irreducible polynomials with prescribed trace and norm

Marko Moisio
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Abstract

Let $\F_q$ ($q=p^r$) be a finite field. In this paper the number of irreducible polynomials of degree $m$ in $\F_q[x]$ with prescribed trace and norm coefficients is calculated in certain special cases and a general bound for that number is obtained improving the bound by Wan if $m$ is small compared to $q$. As a corollary, sharp bounds are obtained for the number of elements in $\F_{q^3}$ with prescribed trace and norm over $\F_q$ improving the estimates by Katz in this special case. Moreover, a characterization of Kloosterman sums over $\F_{2^r}$ divisible by three is given generalizing the earlier result by Charpin, Helleseth, and Zinoviev obtained only in the case $r$ odd. Finally, a new simple proof for the value distribution of a Kloosterman sum over the field $\F_{3^r}$, first proved by Katz and Livne, is given.

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Marko Moisio. 2007-11-21. Kloosterman sums, elliptic curves, and irreducible polynomials with prescribed trace and norm. https://doi.org/10.4064/aa132-4-3

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