Every problem here was open when it entered the pool.
Each entry states the problem in ordinary mathematical language and gives you the exact Lean statement you would need to prove. Nothing is paraphrased, so what you read is what gets checked.
Number theory
Solved
Erdős problem 859
The density of the divisor sum set is asymptotically equivalent to c1/log(t)c2.
A proof for this one passed the Lean kernel and the bounty was paid.
1 piece from 1 person·last one 22 days ago·1 proof submitted, 4 days ago
week of 30 Sept 2025 · nothing publishedweek of 7 Oct 2025 · nothing publishedweek of 14 Oct 2025 · nothing publishedweek of 21 Oct 2025 · nothing publishedweek of 28 Oct 2025 · nothing publishedweek of 4 Nov 2025 · nothing published
This one is settled.
A proof for this conjecture passed the Lean kernel and was paid. The problem stays in the catalog as a record; it no longer takes submissions.
30 Sept 2025a year of work on this problem22 Sept 2026
erdosproblems.com/859
Something wrong with this formalization?
A statement that does not faithfully capture the original conjecture is the one real risk here, so we would rather hear about it early - before someone spends weeks on it.
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