English

Reconstructibility of the $K_r$-count from $n-1$ cards

Combinatorics 2024-02-21 v5

Abstract

The Reconstruction Conjecture of Kelly and Ulam states that any graph GG with n3n\geq 3 vertices can be reconstructed from the multiset D(G)\mathcal{D}(G) of unlabelled subgraphs GvG-v for all vV(G)v\in V(G). We refer to D(G)\mathcal{D}(G) as the \emph{deck} of GG and GvD(G)G-v\in \mathcal{D}(G) as the cards of GG. This was posed in the 1940s and is still wide open today. In an effort to understand reconstructibility better, a growing collection of research is concerned with understanding what properties of GG can be reconstructed from a (potentially adversarially chosen) collection of kk cards for some k<nk< n. In this paper, we show that the clique count of GG is reconstructible for all but one size of clique from any n1n-1 cards. We extend this result by showing that for graphs with average degree at most 3n/8O(1)3n/8-O(1) we can reconstruct the KrK_r-count for all rr, and that for rlog2nr\le \log_2 n we can reconstruct the KrK_r-count for every graph on nn vertices.

Keywords

Cite

@article{arxiv.2112.03366,
  title  = {Reconstructibility of the $K_r$-count from $n-1$ cards},
  author = {Charlotte Knierim and Anders Martinsson},
  journal= {arXiv preprint arXiv:2112.03366},
  year   = {2024}
}

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15 pages