Low-Distortion Embeddings of Trees

نویسندگان

  • Robert Babilon
  • Jirí Matousek
  • Jana Maxová
  • Pavel Valtr
چکیده

We prove that every tree T = (V,E) on n vertices with edges of unit length can be embedded in the plane with distortion O( √ n); that is, we construct a mapping f :V → R such that ρ(u, v) ≤ ‖f(u) − f(v)‖ ≤ O( √ n) · ρ(u, v) for every u, v ∈ V , where ρ(u, v) denotes the length of the path from u to v in T . The embedding is described by a simple and easily computable formula. This is asymptotically optimal in the worst case. We also construct interesting optimal embeddings for a special class of trees (fans consisting of paths of the same length glued together at a common vertex). Communicated by: P. Mutzel and M. Jünger; submitted May 2002; revised April 2003. The research was supported by project LN00A056 of the Ministry of Education of the Czech Republic and by Charles University grants No. 158/99 and 159/99. R. Babilon et al., Embeddings of Trees, JGAA, 7(4) 399–409 (2003) 400

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تاریخ انتشار 2001