🤖 AI Summary
This work extends Wall–Sun–Sun primes to general quadratic fields ℚ(√d) by introducing WSS(d) primes derived from second-order linear recurrence sequences generated by the fundamental unit of ℚ(√d). Based on these primes, cyclic codes are constructed whose parity-check polynomials are reciprocals of the characteristic polynomials of the associated recurrences. By integrating tools from algebraic number theory—particularly p-rationality and properties of quadratic fields—with finite field theory and coding techniques, the paper systematically analyzes the weight distributions of the resulting cyclic codes over 𝔽_p and ℤ_{p²}. The main contribution lies in establishing, for the first time, a connection among WSS(d) primes, the weight distribution of cyclic codes, and p-rationality. Furthermore, the study proves the existence of MDS codes in the reducible case and NMDS codes in the irreducible case.
📝 Abstract
Wall-Sun-Sun primes (shortly WSS primes) are defined as those primes $p$ such that the period of the Fibonacci recurrence is the same modulo
$p$ and modulo $p^2.$ This concept has been generalized recently to certain second order recurrences whose characteristic polynomials admit as a zero the principal unit of $\mathbb{Q}(\sqrt{d}),$
for some integer $d>0.$ Primes of the latter type we call $WSS(d).$ They correspond to the case when $\mathbb{Q}(\sqrt{d})$ is not $p$-rational. For such a prime $p$
we study the weight distributions of the cyclic codes over $\mathbb{F}_p$ and $\mathbb{Z}_{p^2}$ whose
check polynomial is the reciprocal of the said characteristic polynomial. Some of these codes are MDS (reducible case) or NMDS (irreducible case).