Breakthrough Tracker record

Optimal Bounds for Open Addressing Without Reordering

The authors constructed open-addressed hash tables with better-than-expected search bounds, disproving the central conjecture in Andrew Yao's “Uniform Hashing Is Optimal.” They also proved matching lower bounds for the models studied.

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Stable ID
open-addressing-yao-counterexample-2024
Revision
open-addressing-yao-counterexample-2024.v1
Field
Computer Science · Data structures, hashing and combinatorics
Evidence
Tier 1 · Peer reviewed: Yes
Record state
Current · Disproof by counterexample; verified conference result
Last checked

AI role

No AI assistance was disclosed in the paper or linked reporting.

Record details

Problem or result
Expected search and insertion costs in open-addressed hash tables without reordering
Authors
Martín Farach-Colton, Andrew Krapivin and William Kuszmaul
Institutions
New York University, University of Cambridge and Carnegie Mellon University
Result date
FOCS 2024; arXiv version January 4, 2025

Why it matters

The paper replaces a presumed 40-year-old barrier for one of computer science's most basic data structures with optimal bounds.

Limits

The result concerns a defined open-addressing model without reordering. It does not show that every real-world hash-table implementation should be replaced, and immediate engineering performance was not demonstrated.

Sources

  1. Primary: Primary paper on arXiv
  2. Primary: IEEE FOCS 2024 proceedings record
  3. Independent: Quanta Magazine explanation

Correction and revision history

  1. Initial entry.

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