English

Extremal sequences related to the Jacobi symbol

Number Theory 2022-12-13 v2 Combinatorics

Abstract

For a weight-set AZnA\subseteq \mathbb Z_n, the AA-weighted zero-sum constant CA(n)C_A(n) is defined to be the smallest natural number kk, such that any sequence of kk elements in Zn\mathbb Z_n has an AA-weighted zero-sum subsequence of consecutive terms. A sequence of length CA(n)1C_A(n)-1 in Zn\mathbb Z_n which does not have any AA-weighted zero-sum subsequence of consecutive terms will be called a CC-extremal sequence for AA. Let (xn)\big(\frac{x}{n}\big) denote the Jacobi symbol of xZnx\in\mathbb Z_n. We characterize the CC-extremal sequences for the weight-set S(n)={xU(n):(xn)=1}S(n)=\big\{\,x\in U(n):\big(\frac{x}{n}\big)=1\,\big\} and for the weight-set L(n;p)={xU(n):(xn)=(xp)}L(n;p)=\big\{\,x\in U(n):\big(\frac{x}{n}\big)=\big(\frac{x}{p}\big)\,\big\} where pp is a prime divisor of nn. We can define DD-extremal sequences for these weight-sets in a way analogous to the definition of CC-extremal sequences. We also characterize these sequences.

Keywords

Cite

@article{arxiv.2201.00127,
  title  = {Extremal sequences related to the Jacobi symbol},
  author = {Santanu Mondal and Krishnendu Paul and Shameek Paul},
  journal= {arXiv preprint arXiv:2201.00127},
  year   = {2022}
}

Comments

15 pages. arXiv admin note: substantial text overlap with arXiv:2111.14477