English

Shannon capacity, Chess, DNA and Umbrellas

Information Theory 2021-08-12 v1 math.IT

Abstract

A vexing open problem in information theory is to find the Shannon capacity of odd cyclic graphs larger than the pentagon and especially for the heptagon. Lower bounds for the capacity are obtained by solving King chess puzzles. Upper bounds are obtained by solving entanglement problems, that is to find good Lovasz umbrellas, quantum state realizations of the graph. We observe that optimal states are always pure states. The rest is expository. One general interesting question is whether the Shannon capacity is always some n-th root of the independence number of the n'th power of the graph.

Cite

@article{arxiv.2108.04994,
  title  = {Shannon capacity, Chess, DNA and Umbrellas},
  author = {Oliver Knill},
  journal= {arXiv preprint arXiv:2108.04994},
  year   = {2021}
}

Comments

14 pages 11 figures

R2 v1 2026-06-24T05:00:46.707Z