• Title/Summary/Keyword: cyclotomic cosets

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PRIMITIVE IDEMPOTENTS IN THE RING F4[x]/〈xpn-1〉 AND CYCLOTOMIC Q CODES

  • Batra, Sudhir;Mathur, Rekha
    • Bulletin of the Korean Mathematical Society
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    • v.55 no.3
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    • pp.971-997
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    • 2018
  • The parity of cyclotomic numbers of order 2, 4 and 6 associated with 4-cyclotomic cosets modulo an odd prime p are obtained. Hence the explicit expressions of primitive idempotents of minimal cyclic codes of length $p^n$, $n{\geq}1$ over the quaternary field $F_4$ are obtained. These codes are observed to be subcodes of Q codes of length $p^n$. Some orthogonal properties of these subcodes are discussed. The minimal cyclic codes of length 17 and 43 are also discussed and it is observed that the minimal cyclic codes of length 17 are two weight codes. Further, it is shown that a Q code of prime length is always cyclotomic like a binary duadic code and it seems that there are infinitely many prime lengths for which cyclotomic Q codes of order 6 exist.

QUANTUM CODES WITH IMPROVED MINIMUM DISTANCE

  • Kolotoglu, Emre;Sari, Mustafa
    • Bulletin of the Korean Mathematical Society
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    • v.56 no.3
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    • pp.609-619
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    • 2019
  • The methods for constructing quantum codes is not always sufficient by itself. Also, the constructed quantum codes as in the classical coding theory have to enjoy a quality of its parameters that play a very important role in recovering data efficiently. In a very recent study quantum construction and examples of quantum codes over a finite field of order q are presented by La Garcia in [14]. Being inspired by La Garcia's the paper, here we extend the results over a finite field with $q^2$ elements by studying necessary and sufficient conditions for constructions quantum codes over this field. We determine a criteria for the existence of $q^2$-cyclotomic cosets containing at least three elements and present a construction method for quantum maximum-distance separable (MDS) codes. Moreover, we derive a way to construct quantum codes and show that this construction method leads to quantum codes with better parameters than the ones in [14].

MODIFIED CYCLOTOMIC POLYNOMIALS

  • Ae-Kyoung, Cha;Miyeon, Kwon;Ki-Suk, Lee;Seong-Mo, Yang
    • Bulletin of the Korean Mathematical Society
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    • v.59 no.6
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    • pp.1511-1522
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    • 2022
  • Let H be a subgroup of $\mathbb{Z}^*_n$ (the multiplicative group of integers modulo n) and h1, h2, …, hl distinct representatives of the cosets of H in $\mathbb{Z}^*_n$. We now define a polynomial Jn,H(x) to be $$J_{n,H}(x)=\prod^l_{j=1} \left( x-\sum_{h{\in}H} {\zeta}^{h_jh}_n\right)$$, where ${\zeta}_n=e^{\frac{2{\pi}i}{n}}$ is the nth primitive root of unity. Polynomials of such form generalize the nth cyclotomic polynomial $\Phi_n(x)={\prod}_{k{\in}\mathbb{Z}^*_n}(x-{\zeta}^k_n)$ as Jn,{1}(x) = Φn(x). While the nth cyclotomic polynomial Φn(x) is irreducible over ℚ, Jn,H(x) is not necessarily irreducible. In this paper, we determine the subgroups H for which Jn,H(x) is irreducible over ℚ.

SIMPLE-ROOT NEGACYCLIC CODES OF LENGTH 2pnm OVER A FINITE FIELD

  • SHARMA, ANURADHA
    • Journal of the Korean Mathematical Society
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    • v.52 no.5
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    • pp.965-989
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    • 2015
  • Let p, ${\ell}$ be distinct odd primes, q be an odd prime power with gcd(q, p) = gcd(q,${\ell}$) = 1, and m, n be positive integers. In this paper, we determine all self-dual, self-orthogonal and complementary-dual negacyclic codes of length $2p^{n{\ell}m}$ over the finite field ${\mathbb{F}}_q$ with q elements. We also illustrate our results with some examples.

MINIMAL QUADRATIC RESIDUE CYCLIC CODES OF LENGTH $2^{n}$

  • BATRA SUDHIR;ARORA S. K.
    • Journal of applied mathematics & informatics
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    • v.18 no.1_2
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    • pp.25-43
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    • 2005
  • Let F be a finite field of prime power order q(odd) and the multiplicative order of q modulo $2^{n}\;(n>1)\;be\; {\phi}(2^{n})/2$. If n > 3, then q is odd number(prime or prime power) of the form $8m{\pm}3$. If q = 8m - 3, then the ring $R_{2^n} = F[x]/ < x^{2^n}-1 >$ has 2n primitive idempotents. The explicit expressions for these primitive idempotents are obtained and the minimal QR cyclic codes of length $2^{n}$ generated by these idempotents are completely described. If q = 8m + 3 then the expressions for the 2n - 1 primitive idempotents of $R_{2^n}$ are obtained. The generating polynomials and the upper bounds of the minimum distance of minimal QR cyclic codes generated by these 2n-1 idempotents are also obtained. The case n = 2,3 is dealt separately.