Complexity of integer all-pairs shortest paths
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For all-pairs shortest paths with polynomially bounded integer inputs in the specified word-RAM model, the retained deterministic running-time target is O(n^2.99791). Arithmetic and reduction costs are part of the claim.
Why it matters and what counts as progress
Why it matters: It refines a subcubic exponent within an existing framework, rather than representing a separate new framework for overcoming the cubic barrier.
What counts as progress: A faster all-pairs-shortest-path algorithm in the stated bounded-integer model, with the reduction cost included in the running-time exponent.
How the problem developed
- 1962 · Baseline algorithm [1]
Robert W. Floyd Published a cubic-time all-pairs shortest-path algorithm, a baseline that remained standard for decades.
- 2018 · Algorithmic improvement [2]
Virginia Vassilevska Williams Used the polynomial method to improve general APSP by a superpolylogarithmic factor over cubic time, without obtaining a truly subcubic algorithm.
- 5 Oct 2026 · Subcubic algorithm [3]
Josh Alman and Virginia Vassilevska Williams Reported an O(n^2.9995)-time APSP algorithm for polynomially bounded integer weights in the word-RAM model.
- 8 Oct 2026 · Exponent refinement [4]
Improved-exponents project Reported a deterministic O(n^2.99791) bound under the pinned formalization’s stated input assumptions.
AI contributions 2
Claude agents tighten the formalized 3SUM and APSP exponents
Deterministic integer 3SUM in O(n^1.99896) and APSP in O(n^2.99791) in the pinned upstream word RAM model, for polynomially bounded input numbers.
Truly Subquadratic 3SUM and Truly Subcubic APSP via Triangles in Sparse Lopsided Graphs
Claude’s original sparse-output thin-matrix multiplication algorithm, as presented in Section 2 and related to the certified 3SUM/APSP theorems. Human-optimized numerical parameters, new reductions, data structures and Hinted OMv extensions retain human credit.
Sources
- Robert W. Floyd · Algorithm 97: Shortest path (1962)
- Virginia Vassilevska Williams · From circuit complexity to faster all-pairs shortest paths (2018)
- Alman–Vassilevska Williams: algorithms and methodology
- Improved-exponents project and contribution scope
- Completed Lean solution module
- Comparator check log
- Formalization project
Website timeline
Publication dates and editorial changes.
Claude agents tighten the formalized 3SUM and APSP exponents
Claude-assisted truly subquadratic 3SUM and subcubic shortest paths