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Erdős Problem #1026 — Monotonic Subsequence Sums

Erdős problem #1026 · erdosproblems.com/1026

For a sequence of n distinct reals, determine the largest constant c such that some monotonic subsequence always has sum exceeding (c−o(1))·(1/√n)·(total sum). Resolved as c = 1.

Result
Proved
Field
Combinatorics
Posed by
Paul Erdős
Year posed
1971
Years open
54y
Solved
2025-12-08
Model
Aristotle, with GPT, Gemini and AlphaEvolve also contributing
Vendor
Harmonic / OpenAI / Google DeepMind
Collaborators
Boris Alexeev, Stijn Cambie, Terence Tao, Lawrence Wu
Verification
Expert-verified
Notability
No dedicated article

What the AI did

Multiple AI systems contributed within an ordinary human mathematical collaboration rather than one model solving it outright; Aristotle produced and formally verified the winning proof in Lean, pinning down the sharp constant c = 1.

Verification

Formally verified in Lean. Documented firsthand by Terence Tao on his blog as a case study in AI-assisted collaboration, not an AI-alone result.

Source

Terence Tao's blog