TY - JOUR

T1 - Some low distortion metric ramsey problems

AU - Bartal, Yair

AU - Linial, Nathan

AU - Mendel, Manor

AU - Naor, Assaf

PY - 2005/1

Y1 - 2005/1

N2 - In this note we consider the metric Ramsey problem for the normed spaces ℓp. Namely, given some 1 ≤ p ≤ ∞ and α ≥ 1, and an integer n, we ask for the largest m such that every n-point metric space contains an m-point subspace which embeds into ℓp with distortion at most α. In [1] it is shown that in the case of ℓ2, the dependence of m on α undergoes a phase transition at α = 2. Here we consider this problem for other ℓp, and specifically the occurrence of a phase transition for p ≠ 2. It is shown that a phase transition does occur at α = 2 for every p ∈ [1, 2]. For p > 2 we are unable to determine the answer, but estimates are provided for the possible location of such a phase transition. We also study the analogous problem for isometric embedding and show that for every 1 < p < ∞ there are arbitrarily large metric spaces, no four points of which embed isometrically in ℓp.

AB - In this note we consider the metric Ramsey problem for the normed spaces ℓp. Namely, given some 1 ≤ p ≤ ∞ and α ≥ 1, and an integer n, we ask for the largest m such that every n-point metric space contains an m-point subspace which embeds into ℓp with distortion at most α. In [1] it is shown that in the case of ℓ2, the dependence of m on α undergoes a phase transition at α = 2. Here we consider this problem for other ℓp, and specifically the occurrence of a phase transition for p ≠ 2. It is shown that a phase transition does occur at α = 2 for every p ∈ [1, 2]. For p > 2 we are unable to determine the answer, but estimates are provided for the possible location of such a phase transition. We also study the analogous problem for isometric embedding and show that for every 1 < p < ∞ there are arbitrarily large metric spaces, no four points of which embed isometrically in ℓp.

UR - http://www.scopus.com/inward/record.url?scp=11944272962&partnerID=8YFLogxK

U2 - 10.1007/s00454-004-1100-z

DO - 10.1007/s00454-004-1100-z

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AN - SCOPUS:11944272962

SN - 0179-5376

VL - 33

SP - 27

EP - 41

JO - Discrete and Computational Geometry

JF - Discrete and Computational Geometry

IS - 1

ER -