Exponential Sums, Cyclic Codes and Sequences: the Odd Characteristic Kasami Case

Let $q=p^n$ with $n=2m$ and $p$ be an odd prime. Let $0\leq k\leq n-1$ and $k\neq m$. In this paper we determine the value distribution of following exponential(character) sums [\sum\limits_{x\in \bF_q}\zeta_p^{\Tra_1^m (\alpha x^{p^{m}+1})+\Tra_1^n(\beta x^{p^k+1})}\quad(\alpha\in \bF_{p^m},\beta\in \bF_{q})] and [\sum\limits_{x\in \bF_q}\zeta_p^{\Tra_1^m (\alpha x^{p^{m}+1})+\Tra_1^n(\beta x^{p^k+1}+\ga x)}\quad(\alpha\in \bF_{p^m},\beta,\ga\in \bF_{q})] where $\Tra_1^n: \bF_q\ra \bF_p$ and $\Tra_1^m: \bF_{p^m}\ra\bF_p$ are the canonical trace mappings and $\zeta_p=e^{\frac{2\pi i}{p}}$ is a primitive $p$-th root of unity. As applications: (1). We determine the weight distribution of the cyclic codes $\cC_1$ and $\cC_2$ over $\bF_{p^t}$ with parity-check polynomials $h_2(x)h_3(x)$ and $h_1(x)h_2(x)h_3(x)$ respectively where $t$ is a divisor of $d=\gcd(m,k)$, and $h_1(x)$, $h_2(x)$ and $h_3(x)$ are the minimal polynomials of $\pi^{-1}$, $\pi^{-(p^k+1)}$ and $\pi^{-(p^m+1)}$ over $\bF_{p^t}$ respectively for a primitive element $\pi$ of $\bF_q$. (2). We determine the correlation distribution among a family of m-sequences. This paper extends the results in \cite{Zen Li}.

💡 Research Summary

The paper studies exponential (character) sums over finite fields of odd characteristic and applies the results to cyclic codes and m‑sequences. Let (q=p^{n}) with (n=2m) and (p) an odd prime. For an integer (k) satisfying (0\le k\le n-1) and (k\neq m), define two families of sums \