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Record W2971434485 · doi:10.1109/focs.2019.00069

Truly Optimal Euclidean Spanners

2019· article· en· W2971434485 on OpenAlex
Hung Le, Shay Solomon

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.

Bibliographic record

Venuenot available
Typearticle
Languageen
FieldComputer Science
TopicComputational Geometry and Mesh Generation
Canadian institutionsUniversity of Victoria
Fundersnot available
KeywordsSpannerCombinatoricsEuclidean geometryDimension (graph theory)Euclidean spaceMathematicsGreedy algorithmInverseEuclidean distanceDiscrete mathematicsComputer scienceAlgorithmGeometry

Abstract

fetched live from OpenAlex

Euclidean spanners are important geometric structures, having found numerous applications over the years. Cornerstone results in this area from the late 80s and early 90s state that for any d-dimensional n-point Euclidean space, there exists a (1+ε) -spanner with O(nε^-d+1) edges and lightness (normalized weight) O(ε^-2d)^1. Surprisingly, the fundamental question of whether or not these dependencies on ε and d for small d can be improved has remained elusive, even for d = 2. This question naturally arises in any application of Euclidean spanners where precision is a necessity (thus ε is tiny). In the most extreme case ε is inverse polynomial in n, and then one could potentially improve the size and lightness bounds by factors that are polynomial in n. The state-of-the-art bounds O(nε^-d+1) and O(ε^-2d) on the size and lightness of spanners are realized by the greedy spanner. In 2016, Filtser and Solomon [25] proved that, in low dimensional spaces, the greedy spanner is “near-optimal''; informally, their result states that the greedy spanner for dimension d is just as sparse and light as any other spanner but for dimension larger by a constant factor. Hence the question of whether the greedy spanner is truly optimal remained open to date. The contribution of this paper is two-fold. 1) We resolve these longstanding questions by nailing down the exact dependencies on ε and d and showing that the greedy spanner is truly optimal. Specifically, for any d= O(1), ε = Ω(n^-1/d-1): • We show that any (1+ε) -spanner must have Ω(nε^-d+1) edges, implying that the greedy (and other) spanners achieve the optimal size. • We show that any (1+ε) -spanner must have lightness Ω(ε^-d), and then improve the upper bound on the lightness of the greedy spanner from O(ε^-2d) to Õ_ε (ε^-d). 2) We then complement our negative result for the size of spanners with a rather counterintuitive positive result: Steiner points lead to a quadratic improvement in the size of spanners! Our bound for the size of Steiner spanners is tight as well (up to lower-order terms).

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesInsufficient payload (model declined to judge)
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Simulation or modeling · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: none
Teacher disagreement score0.820
Threshold uncertainty score1.000

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.000
Science and technology studies0.0000.000
Scholarly communication0.0000.000
Open science0.0000.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.001

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.006
GPT teacher head0.213
Teacher spread0.207 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it