A linear code can be thought of as a vector matroid represented by the columns of the code's generator matrix;a well-known result in this context is Greene's theorem on a connection of the weight polynomial of...
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A linear code can be thought of as a vector matroid represented by the columns of the code's generator matrix;a well-known result in this context is Greene's theorem on a connection of the weight polynomial of the code and the Tutte polynomial of the matroid. W examine this connection from the coding-theoretic viewpoint, building upon the rank polynomial of the code. This enables us to obtain bounds on all-terminal reliability of linear matroids and new proofs of two known results: Greene's theorem and a connection between the weight polynomial and the partition polynomial of the Potts model.
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, ...
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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 k/2 -1 -q+1 <= d <= q(k-1)-q(k/2) - q k2/1 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).
Let q = 2(m). The projective general linear group PGL(2, q) acts as a 3-transitive permutation group on the set of points of the projective line. The first objective of this paper is to prove that all linear codes ove...
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Let q = 2(m). The projective general linear group PGL(2, q) acts as a 3-transitive permutation group on the set of points of the projective line. The first objective of this paper is to prove that all linear codes over GF(2(h)) that are invariant under PGL(2, q) are trivial codes: the repetition code, the whole space GF(2(h))2(m)+1, and their dual codes. As an application of this result, the 2-ranks of the (0,1)-incidence matrices of all 3 - (q + 1, k, lambda) designs that are invariant under PGL(2, q) are determined. The second objective is to present two infinite families of cyclic codes over GF(2(m)) such that the set of the supports of all codewords of any fixed nonzero weight is invariant under PGL(2, q), therefore, the codewords of any nonzero weight support a 3-design. A code from the first family has parameters [q + 1, q - 3, 4] q, where q = 2(m), and m >= 4 is even. The exact number of the codewords of minimum weight is determined, and the codewords of minimum weight support a 3-(q + 1, 4, 2) design. A code from the second family has parameters [q + 1, 4, q - 4] q, q = 2(m), m >= 4 even, and the minimum weight codewords support a 3-(q + 1, q - 4, (q - 4)(q - 5)(q - 6)/60) design, whose complementary 3-(q + 1, 5, 1) design is isomorphic to the Witt spherical geometry with these parameters. A lower bound on the dimension of a linear code over GF(q) that can support a 3-(q + 1, q - 4, (q - 4)(q - 5)(q - 6)/60) design is proved, and it is shown that the designs supported by the codewords of minimum weight in the codes from the second family of codes meet this bound.
Two general constructions of linear codes with functions over finite fields have been extensively studied in the literature. The first one is given by C(f) = {Tr(af (x) + bx) x is an element of F-qm* :a, b is an eleme...
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Two general constructions of linear codes with functions over finite fields have been extensively studied in the literature. The first one is given by C(f) = {Tr(af (x) + bx) x is an element of F-qm* :a, b is an element of F-q(m)}, where q is a prime power, F-q(m) = F-q(m) \ linear code, Tr is the trace function from F-q(m) to F-q, and f (x) is a function from F-q(m) to F-q(m) with f (0) = 0. Almost bent functions, quadratic functions and some monomials on F-2(m) were used in the first construction, and many families of binary linear codes with few weights were obtained in the literature. This paper studies some punctured codes of these binary codes. Several families of binary linear codes with few weights and new parameters are obtained in this paper. Several families of distance-optimal binary linear codes with new parameters are also produced in this paper.
In this paper, we determine the smallest lengths of linear codes with some minimum distances. We construct a [g(q)(k, d) + 1, k,d](q) code for sq(k-1) - sq(k-2) - q(s) - q(2)+ 1 = s + 1. Then we get n(q) (k,d) = g(q)(...
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In this paper, we determine the smallest lengths of linear codes with some minimum distances. We construct a [g(q)(k, d) + 1, k,d](q) code for sq(k-1) - sq(k-2) - q(s) - q(2)+ 1 <= d <= sq(k-1) - sq(k-2) - q(s) with 3 <= s <= k-2 and q >= s + 1. Then we get n(q) (k,d) = g(q)(k,d) + 1 for (k -2)q(k-1) - (k-1)q(k-2) - q(2) + 1 <= d <= (k -2)q(k-1) - (k-1)q(k-2), k >= 6, q >= 2k-3;and sq(k-1) - sq(k-2) - q(s) - q + 1 <= d <= sq(k-1) - sq(k-2) - q(s), s >= 2, k >= 2s + 1 and q >= 2s -1.
Locally recoverable codes (LRCs) were proposed for the recovery of data in distributed and cloud storage systems about nine years ago. A lot of progress on the study of LRCs has been made by now. However, there is a l...
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Locally recoverable codes (LRCs) were proposed for the recovery of data in distributed and cloud storage systems about nine years ago. A lot of progress on the study of LRCs has been made by now. However, there is a lack of general theory on the minimum locality of linear codes. In addition, the minimum locality of many known families of linear codes has not been studied in the literature. Motivated by these two facts, this paper develops some general theory about the minimum locality of linear codes, and investigates the minimum locality of a number of families of linear codes, such as q-ary Hamming codes, q-ary Simplex codes, generalized Reed-Muller codes, ovoid codes, maximum arc codes, the extended hyperoval codes, and near MDS codes. Many classes of both distance-optimal and dimension-optimal LRCs are presented in this paper. To this end, the concepts of linear locality and minimum linear locality are specified. The minimum linear locality of many families of linear codes are settled with the general theory developed in this paper.
Minimal linear codes have important applications in secure communications, including in the framework of secret sharing schemes and secure multi-party computation. A lot of research have been carried out to derive cod...
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Minimal linear codes have important applications in secure communications, including in the framework of secret sharing schemes and secure multi-party computation. A lot of research have been carried out to derive codes with few weights (but more importantly, being minimal) using algebraic or geometric approaches. One of the main power and fructify algebraic methods is based on the design of those codes by employing functions over finite fields. Li et al. (2021) have recently identified some binary linear codes with few weights from two classes of two- to-one functions. In this paper, our ultimate objective is to expand the class of codes derived from the paper of Li et al. by proposing larger classes of binary linear codes with few weights via generic constructions involving other known families of two-to-one functions over the finite field F2(n) of order 2(n). We succeed in constructing such codes, and we also completely determine their weight distributions. The linear codes presented in this paper differ in parameters from those known in the literature. Besides, some of them are optimal concerning the well-known Griesmer bound. Notably, we prove that our codes are either optimal or almost optimal with respect to the online Database of Grassl. We next observe that the derived binary linear codes also have the minimality property for most cases. We then describe the access structures of the secret-sharing schemes based on their dual codes. Finally, we solve two problems left open in the paper by Li et al. (more specifically, a complete solution to Problem 2 and a partial solution to Problem 1).
Recently, linear codes with few weights have been widely studied, since they have applications in data storage systems, communication systems and consumer electronics. In this paper, we present a class of three-weight...
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Recently, linear codes with few weights have been widely studied, since they have applications in data storage systems, communication systems and consumer electronics. In this paper, we present a class of three-weight and five-weight linear codes over F-p, where p is an odd prime and F-p denotes a finite field with p elements. The weight distributions of the linear codes constructed in this paper are also settled. Moreover, the linear codes illustrated in the paper may have applications in secret sharing schemes. (C) 2016 Published by Elsevier B.V.
Some of the upper bounds given by T. Verhoeff (1987) are improved by proving the nonexistence of codes with certain parameters. Necessary preliminary results are stated. The results give rise to upper bounds on d(n, k...
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Some of the upper bounds given by T. Verhoeff (1987) are improved by proving the nonexistence of codes with certain parameters. Necessary preliminary results are stated. The results give rise to upper bounds on d(n, k) for many further values of (n, k) by using simple standard techniques. The further bounds would automatically follow from theorems by using Verhoeff's computerized updating program, but the authors state them here because several of them are required in the proofs of subsequent theorems.< >
In this paper, we mainly study the theory of linear codes over the ring R = Z(4) + uZ(4) + nu Z(4) + u nu Z(4). By using the Chinese Remainder Theorem, we prove that R is isomorphic to a direct sum of four rings. We d...
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In this paper, we mainly study the theory of linear codes over the ring R = Z(4) + uZ(4) + nu Z(4) + u nu Z(4). By using the Chinese Remainder Theorem, we prove that R is isomorphic to a direct sum of four rings. We define a Gray map Phi from R-n to Z(4)(4n), which is a distance preserving map. The Gray image of a cyclic code over R is a linear code over Z(4). We also discuss some properties of MDS codes over R. Furthermore, we study the MacWilliams identities of linear codes over R and give the generator polynomials of cyclic codes over R.
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