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2024, arXiv (Cornell University)
The hull of a linear code C is the intersection of C with its dual code. We present and analyze the number of linear q-ary codes of the same length and dimension but with different dimensions for their hulls. We prove that for given dimension k and length n ≥ 2k the number of all [n, k] q linear codes with hull dimension l decreases as l increases. We also present classification results for binary and ternary linear codes with trivial hulls (LCD and self-orthogonal) for some values of the length n and dimension k, comparing the obtained numbers with the number of all linear codes for the given n and k.
arXiv (Cornell University), 2023
The Euclidean hull of a linear code C is defined as C ∩ C ⊥ , where C ⊥ denotes the dual of C under the Euclidean inner product. A linear code with zero hull dimension is called a linear complementary dual (LCD) code. A pair (C, D) of linear codes of length n over F q is called a linear complementary pair (LCP) of codes if C ⊕ D = F n q. In this paper, we give a characterization of LCD and LCP of cyclic codes of length q m − 1, m ≥ 1, over the finite field F q in terms of their basic dual zeros and their trace representations. We also formulate the hull dimension of a cyclic code of arbitrary length over F q with respect to its basic dual zero. Moreover, we provide a general formula for the dimension of the intersection of two cyclic codes of arbitrary length over F q based on their basic dual zeros.
Finite Fields and Their Applications, 2005
A complete classification is given of all [22, 111 and [24, 121 binary self-dual codes. For each code we give the order of its group, the number of codes equivalent to it, and its weight distribution. There is a unique [24, 12, 61 selfdual code. Several theorems on the enumeration of self-dual codes are used, including formulas for the number of such codes with minimum distance > 4, and for the sum of the weight enumerators of all such codes of length n. Selforthogonal codes which are generated by code words of weight 4 are completely characterized.
Given an (n, k) linear code C over GF(q), the intersection of C with a code ?(C), where ? # S n , is an (n, k 1 ) code, where max[0, 2k&n] k 1 k. The intersection problem is to determine which integers in this range are attainable for a given code C. We show that, depending on the structure of the generator matrix of the code, some of the values in this range are attainable. As a consequence we give a complete solution to the intersection problem for most of the interesting linear codes, e.g. cyclic codes, Reed Muller codes, and most MDS codes.
Discrete Mathematics, 1985
We study pairs of binary linear codes Cl(n, nR1), C2(n, nR 2) with the property that for any nonzero cl c C~ and c2~ C 2, there are coordinates in which both c, and c 2 are nonzero. * This work was done while he was visiting at the Technion, Haifa, Israel. 0012-365X/85/$3.30 (~) 1985, Elsevier Science Publishers B.V. (North-Holland)
2017
In this paper we investigate linear codes with complementary dual (LCD) codes and formally self-dual codes over the ring R = F q + vF q + v 2 F q , where v 3 = v, for q odd. We give conditions on the existence of LCD codes and present construction of formally self-dual codes over R. Further, we give bounds on the minimum distance of LCD codes over F q and extend these to codes over R.
2002
The rank of a q-ary code C of length n, r (C), is the dimension of the subspace spanned by C. We establish the existence of q-ary 1-perfect codes of length n = q m −1 q−1 for m ≥ 4 and r (C) = n − m + s for each s ∈ {1,. .. , m}. This is a generalization of the binary case proved by Etzion and Vardy in [4].
arXiv (Cornell University), 2017
The hulls of linear and cyclic codes have been extensively studied due to their wide applications. The dimensions and average dimension of the Euclidean hull of linear and cyclic codes have been well-studied. In this paper, the average dimension of the Hermitian hull of constacyclic codes of length n over a finite field F q 2 is determined together with some upper and lower bounds. It turns out that either the average dimension of the Hermitian hull of constacyclic codes of length n over F q 2 is zero or it grows the same rate as n. Comparison to the average dimension of the Euclidean hull of cyclic codes is discussed as well.
Let an $[n,k,d]_q$ code be a linear code of length $n$, dimension $k$ and minimum Hamming distance $d$ over $GF(q)$. One of the most important problems in coding theory is to construct codes with optimal minimum distances. In this paper 22 new ternary linear codes are presented. Two of them are optimal. All new codes improve the respective lower bounds in [11].
q code be a linear code of length n, dimension k and Hamming minimum distance d over GF(q). In this paper record-breaking codes with parameters [30, 10, 15]5, [
Designs, Codes and Cryptography, 2010
The shortest possible length of a q-ary linear code of covering radius R and codimension r is called the length function and is denoted by q (r, R). Constructions of codes with covering radius 3 are here developed, which improve best known upper bounds on q (r, 3). General constructions are given and upper bounds on q (r, 3) for q = 3, 4, 5, 7 and r ≤ 24 are tabulated.
ArXiv, 2019
The projective space $\mathbb{P}_q(n)$, i.e. the set of all subspaces of the vector space $\mathbb{F}_q^n$, is a metric space endowed with the subspace distance metric. Braun, Etzion and Vardy argued that codes in a projective space are analogous to binary block codes in $\mathbb{F}_2^n$ using a framework of lattices. They defined linear codes in $\mathbb{P}_q(n)$ by mimicking key features of linear codes in the Hamming space $\mathbb{F}_2^n$. In this paper, we prove that a linear code in a projective space forms a sublattice of the corresponding projective lattice if and only if the code is closed under intersection. The sublattice thus formed is geometric distributive. We also present an application of this lattice-theoretic characterization.
2015 Twenty First National Conference on Communications (NCC), 2015
Subspace codes are subsets of the projective space Pq(n), which is the set of all subspaces of the vector space F n q. Koetter and Kschischang argued that subspace codes are useful for error and erasure correction in random network coding. Linearity in subspace codes was defined by Braun, Etzion and Vardy, and they conjectured that the largest cardinality of a linear subspace code in Pq(n) is 2 n. In this paper, we show that the conjecture holds for linear subspace codes that are closed under intersection, i.e., codes having the property that the intersection of any pair of codewords is also a codeword. The proof is via a characterization of such codes in terms of partitions of linearly independent subsets of F n q .
2019
In this paper, a linear l-intersection pair of codes is introduced as a generalization of linear complementary pairs of codes. Two linear codes are said to be a linear l-intersection pair if their intersection has dimension l. Characterizations and constructions of such pairs of codes are given in terms of the corresponding generator and parity-check matrices. Linear l-intersection pairs of MDS codes over Fq of length up to q + 1 are given for all possible parameters. As an application, linear l-intersection pairs of codes are used to construct entanglement-assisted quantum error correcting codes. This provides a large number of new MDS entanglement-assisted quantum error correcting codes.
be the smallest integer n for which there exists a linear code of length n, dimension IC, and minimum distance d, over a field of q elements. In this correspondence we determine n5 (4, d ) for all but 22 values of d. Index Terms-Optimal q-ary linear codes, minimum-length bounds. Publisher Item Identifier S 0018-9448(97)00108-9.
arXiv (Cornell University), 2018
In this paper, a linear ℓ-intersection pair of codes is introduced as a generalization of linear complementary pairs of codes. Two linear codes are said to be a linear ℓ-intersection pair if their intersection has dimension ℓ. Characterizations and constructions of such pairs of codes are given in terms of the corresponding generator and parity-check matrices. Linear ℓ-intersection pairs of MDS codes over F q of length up to q + 1 are given for all possible parameters. As an application, linear ℓ-intersection pairs of codes are used to construct entanglement-assisted quantum error correcting codes. This provides a large number of new MDS entanglement-assisted quantum error correcting codes.
2018
In this paper, a linear l-intersection pair of codes is introduced as a generalization of linear complementary pairs of codes. Two linear codes are said to be a linear lintersection pair if their intersection has dimension l. A characterization of such pairs of codes is given in terms of the corresponding generator and parity-check matrices. Linear l-intersection pairs of MDS codes over Fq of length up to q + 1 are given for all possible parameters. As an application, linear l-intersection pairs of codes are used to construct entanglement-assisted quantum error correcting codes. This provides a large number of new MDS entanglement-assisted quantum error correcting codes.
IEEE Transactions on Information Theory, 2000
Designs, Codes and Cryptography
In this paper, a linear ℓ-intersection pair of codes is introduced as a generalization of linear complementary pairs of codes. Two linear codes are said to be a linear ℓ-intersection pair if their intersection has dimension ℓ. Characterizations and constructions of such pairs of codes are given in terms of the corresponding generator and parity-check matrices. Linear ℓ-intersection pairs of MDS codes over F q of length up to q + 1 are given for all possible parameters. As an application, linear ℓ-intersection pairs of codes are used to construct entanglement-assisted quantum error correcting codes. This provides a large number of new MDS entanglement-assisted quantum error correcting codes.
Designs, Codes and Cryptography, 2007
We determine the minimum length n q (k, d) for some linear codes with k ≥ 5 and q ≥ 3. We prove that n q (k, d) = g q (k, d) + 1 for q k−1 − 2q k−1 2 −q + 1 ≤ d ≤ q k−1 − 2q k−1 2 when k is odd, for q k−1 − q k 2 − q k 2 −1 − q + 1 ≤ d ≤ q k−1 − q k 2 − q k 2 −1 when k is even, and for 2q k−1 − 2q k−2 − q 2 − q + 1 ≤ d ≤ 2q k−1 − 2q k−2 − q 2 .
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