Breakthrough Tracker record
Polynomial improvements refute the standard 3SUM and APSP hypotheses
Alman and Vassilevska Williams give deterministic O(n^1.9992) time for polynomial-size integer 3SUM and O(n^2.9995) time for directed APSP with polynomially bounded integer weights, yielding the first fixed-polynomial exponent improvements over the textbook bounds in those models.
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- Stable ID
cs-3sum-apsp-polynomial-improvements-2026- Revision
cs-3sum-apsp-polynomial-improvements-2026.v1- Field
- Theoretical computer science · Fine-grained complexity, graph algorithms and algebraic algorithms
- Evidence
- Tier 1 · Peer reviewed: No
- Record state
- Provisional · Formalization-backed provisional algorithms
- Last checked
AI role
The paper says an Anthropic Claude model discovered the core algorithm. The human authors understood, simplified, strengthened and extended it, derived consequences and took responsibility. Claude also produced a Lean certification of the headline results.
Record details
- Problem or result
- Truly subquadratic 3SUM and truly subcubic all-pairs shortest paths
- Authors
- Josh Alman and Virginia Vassilevska Williams
- Institutions
- Columbia University; Massachusetts Institute of Technology
- Result date
- First-version preprint submitted October 5, 2026; independent follow-ups submitted later in October
Why it matters
The result overturns two central fine-grained hardness hypotheses in their standard polynomially bounded integer models and transfers through established reductions to a broad family of graph and geometric problems.
Limits
The exponent gains are small and asymptotic, with restrictions on input size and weight models; they are not evidence of practical speedups at ordinary input sizes. The preprint and supplied Lean artifact are not peer review, although independent follow-up manuscripts reproduce and simplify the route.
Sources
- Primary: Alman and Vassilevska Williams 3SUM and APSP algorithms
- Formal proof: Anthropic formalization of the headline claims
- Independent follow-up: Karingula and Lovett simplified proof
- Independent extension: Follow-up improvement for thin selected-entry matrix products
Correction and revision history
- 2026-10-19 — Added after primary-source, scope, status, AI-role and limitation review.
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