English

Completeness-resolvable graphs

Combinatorics 2021-01-11 v1

Abstract

Given a connected graph G=(V(G),E(G))G=(V(G), E(G)), the length of a shortest path from a vertex uu to a vertex vv is denoted by d(u,v)d(u,v). For a proper subset WW of V(G)V(G), let m(W)m(W) be the maximum value of d(u,v)d(u,v) as uu ranging over WW and vv ranging over V(G)WV(G)\setminus W. The proper subset W={w1,,wW}W=\{w_1,\ldots,w_{|W|}\} is a {\em completeness-resolving set} of GG if ΨW:V(G)W[m(W)]W,u(d(w1,u),,d(wW,u)) \Psi_W: V(G)\setminus W \longrightarrow [m(W)]^{|W|},\qquad u\longmapsto (d(w_1,u),\ldots,d(w_{|W|},u)) is a bijection, where [m(W)]W={(a(1),,a(W))1a(i)m(W) for each i=1,,W}. [m(W)]^{|W|}=\{(a_{(1)},\ldots,a_{(|W|)})\mid 1\leq a_{(i)}\leq m(W)\text{ for each }i=1,\ldots,|W|\}. A graph is {\em completeness-resolvable} if it admits a completeness-resolving set. In this paper, we first construct the set of all completeness-resolvable graphs by using the edge coverings of some vertices in given bipartite graphs, and then establish posets on some subsets of this set by the spanning subgraph relationship. Based on each poset, we find the maximum graph and give the lower and upper bounds for the number of edges in a minimal graph. Furthermore, minimal graphs satisfying the lower or upper bound are characterized.

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Cite

@article{arxiv.2101.02838,
  title  = {Completeness-resolvable graphs},
  author = {Min Feng and Xuanlong Ma and Huiling Xu},
  journal= {arXiv preprint arXiv:2101.02838},
  year   = {2021}
}

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20 pages