English

MacWilliams' Extension Theorem for rank-metric codes

Information Theory 2023-04-27 v1 math.IT

Abstract

The MacWilliams' Extension Theorem is a classical result by Florence Jessie MacWilliams. It shows that every linear isometry between linear block-codes endowed with the Hamming distance can be extended to a linear isometry of the ambient space. Such an extension fails to exist in general for rank-metric codes, that is, one can easily find examples of linear isometries between rank-metric codes which cannot be extended to linear isometries of the ambient space. In this paper, we explore to what extent a MacWilliams' Extension Theorem may hold for rank-metric codes. We provide an extensive list of examples of obstructions to the existence of an extension, as well as a positive result.

Cite

@article{arxiv.2304.13341,
  title  = {MacWilliams' Extension Theorem for rank-metric codes},
  author = {Elisa Gorla and Flavio Salizzoni},
  journal= {arXiv preprint arXiv:2304.13341},
  year   = {2023}
}

Comments

12 pages

R2 v1 2026-06-28T10:18:10.588Z