24 research outputs found
A Polymatroid Approach to Generalized Weights of Rank Metric Codes
We consider the notion of a -polymatroid, due to Shiromoto, and the
more general notion of -demi-polymatroid, and show how generalized
weights can be defined for them. Further, we establish a duality for these
weights analogous to Wei duality for generalized Hamming weights of linear
codes. The corresponding results of Ravagnani for Delsarte rank metric codes,
and Martinez-Penas and Matsumoto for relative generalized rank weights are
derived as a consequence.Comment: 22 pages; with minor revisions in the previous versio
The Weight Hierarchies of Linear Codes from Simplicial Complexes
The study of the generalized Hamming weight of linear codes is a significant
research topic in coding theory as it conveys the structural information of the
codes and determines their performance in various applications. However,
determining the generalized Hamming weights of linear codes, especially the
weight hierarchy, is generally challenging. In this paper, we investigate the
generalized Hamming weights of a class of linear code \C over \bF_q, which
is constructed from defining sets. These defining sets are either special
simplicial complexes or their complements in \bF_q^m. We determine the
complete weight hierarchies of these codes by analyzing the maximum or minimum
intersection of certain simplicial complexes and all -dimensional subspaces
of \bF_q^m, where 1\leq r\leq {\rm dim}_{\bF_q}(\C)
The weight hierarchies and chain condition of a class of codes from varieties over finite fields
The generalized Hamming weights of linear codes were first introduced by Wei. These are fundamental parameters related to the minimal overlap structures of the subcodes and very useful in several fields. It was found that the chain condition of a linear code is convenient in studying the generalized Hamming weights of the product codes. In this paper we consider a class of codes defined over some varieties in projective spaces over finite fields, whose generalized Hamming weights can be determined by studying the orbits of subspaces of the projective spaces under the actions of classical groups over finite fields, i.e., the symplectic groups, the unitary groups and orthogonal groups. We give the weight hierarchies and generalized weight spectra of the codes from Hermitian varieties and prove that the codes satisfy the chain condition
Weight hierarchies of a family of linear codes associated with degenerate quadratic forms
We restrict a degenerate quadratic form over a finite field of odd
characteristic to subspaces. Thus, a quotient space related to is
introduced. Then we get a non-degenerate quadratic form induced by over the
quotient space. Some related results on the subspaces and quotient space are
obtained. Based on this, we solve the weight hierarchies of a family of linear
codes related to Comment: 12 page
Hamming weights and Betti numbers of Stanley-Reisner rings associated to matroids
To each linear code over a finite field we associate the matroid of its
parity check matrix. We show to what extent one can determine the generalized
Hamming weights of the code (or defined for a matroid in general) from various
sets of Betti numbers of Stanley-Reisner rings of simplicial complexes
associated to the matroid
Strong Singleton type upper bounds for linear insertion-deletion codes
The insertion-deletion codes was motivated to correct the synchronization
errors. In this paper we prove several Singleton type upper bounds on the
insdel distances of linear insertion-deletion codes, based on the generalized
Hamming weights and the formation of minimum Hamming weight codewords. Our
bound are stronger than some previous known bounds. These upper bounds are
valid for any fixed ordering of coordinate positions. We apply these upper
bounds to some binary cyclic codes and binary Reed-Muller codes with any
coordinate ordering, and some binary Reed-Muller codes and one
algebraic-geometric code with certain special coordinate ordering.Comment: 22 pages, references update