TY - GEN

T1 - Near isometric terminal embeddings for doubling metrics

AU - Elkin, Michael

AU - Neiman, Ofer

N1 - Funding Information:
This research was supported by the ISF grant No. (724/15). 2 Supported in part by the ISF grant 1817/17 and BSF grant 2015813.
Funding Information:
This research was supported by the ISF grant No. (724/15). Supported in part by the ISF grant 1817/17 and BSF grant 2015813.
Publisher Copyright:
© Michael Elkin and Ofer Neiman; licensed under Creative Commons License CC-BY 34th Symposium on Computational Geometry (SoCG 2018).

PY - 2018/6/1

Y1 - 2018/6/1

N2 - Given a metric space (X, d), a set of terminals K ⊆ X, and a parameter t ≥ 1, we consider metric structures (e.g., spanners, distance oracles, embedding into normed spaces) that preserve distances for all pairs in K × X up to a factor of t, and have small size (e.g. number of edges for spanners, dimension for embeddings). While such terminal (aka source-wise) metric structures are known to exist in several settings, no terminal spanner or embedding with distortion close to 1, i.e., t = 1 + ϵ for some small 0 < ϵ < 1, is currently known. Here we devise such terminal metric structures for doubling metrics, and show that essentially any metric structure with distortion 1 + ϵ and size s(|X|) has its terminal counterpart, with distortion 1 + O(ϵ) and size s(|K|) + 1. In particular, for any doubling metric on n points, a set of k = o(n) terminals, and constant 0 < ϵ < 1, there exists • A spanner with stretch 1 + ϵ for pairs in K × X, with n + o(n) edges. • A labeling scheme with stretch 1 + ϵ for pairs in K × X, with label size ≈ log k. • An embedding into ld ∞ with distortion 1 + ϵ for pairs in K × X, where d = O(log k). Moreover, surprisingly, the last two results apply if only K is a doubling metric, while X can be arbitrary.

AB - Given a metric space (X, d), a set of terminals K ⊆ X, and a parameter t ≥ 1, we consider metric structures (e.g., spanners, distance oracles, embedding into normed spaces) that preserve distances for all pairs in K × X up to a factor of t, and have small size (e.g. number of edges for spanners, dimension for embeddings). While such terminal (aka source-wise) metric structures are known to exist in several settings, no terminal spanner or embedding with distortion close to 1, i.e., t = 1 + ϵ for some small 0 < ϵ < 1, is currently known. Here we devise such terminal metric structures for doubling metrics, and show that essentially any metric structure with distortion 1 + ϵ and size s(|X|) has its terminal counterpart, with distortion 1 + O(ϵ) and size s(|K|) + 1. In particular, for any doubling metric on n points, a set of k = o(n) terminals, and constant 0 < ϵ < 1, there exists • A spanner with stretch 1 + ϵ for pairs in K × X, with n + o(n) edges. • A labeling scheme with stretch 1 + ϵ for pairs in K × X, with label size ≈ log k. • An embedding into ld ∞ with distortion 1 + ϵ for pairs in K × X, where d = O(log k). Moreover, surprisingly, the last two results apply if only K is a doubling metric, while X can be arbitrary.

KW - Doubling metrics

KW - Metric embedding

KW - Spanners

UR - http://www.scopus.com/inward/record.url?scp=85048971471&partnerID=8YFLogxK

U2 - 10.4230/LIPIcs.SoCG.2018.36

DO - 10.4230/LIPIcs.SoCG.2018.36

M3 - Conference contribution

AN - SCOPUS:85048971471

T3 - Leibniz International Proceedings in Informatics, LIPIcs

SP - 361

EP - 3615

BT - 34th International Symposium on Computational Geometry, SoCG 2018

A2 - Toth, Csaba D.

A2 - Speckmann, Bettina

PB - Schloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing

T2 - 34th International Symposium on Computational Geometry, SoCG 2018

Y2 - 11 June 2018 through 14 June 2018

ER -