English

Nonapproximablity of the Normalized Information Distance

Computational Complexity 2009-10-23 v2 Information Theory math.IT

Abstract

Normalized information distance (NID) uses the theoretical notion of Kolmogorov complexity, which for practical purposes is approximated by the length of the compressed version of the file involved, using a real-world compression program. This practical application is called `normalized compression distance' and it is trivially computable. It is a parameter-free similarity measure based on compression, and is used in pattern recognition, data mining, phylogeny, clustering, and classification. The complexity properties of its theoretical precursor, the NID, have been open. We show that the NID is neither upper semicomputable nor lower semicomputable up to any reasonable precision.

Keywords

Cite

@article{arxiv.0910.4353,
  title  = {Nonapproximablity of the Normalized Information Distance},
  author = {Sebastiaan A. Terwijn and Leen Torenvliet and Paul M. B. Vitanyi},
  journal= {arXiv preprint arXiv:0910.4353},
  year   = {2009}
}

Comments

LaTeX 8 pages, Submitted. 2nd version corrected some typos

R2 v1 2026-06-21T14:02:13.947Z