Definition
A specific Erdős open problem from 1970 about sumsets of digit-restricted integers, solved autonomously by an AI system in 2026.
Erdős problem 125, asking about the lower density of A+B where A consists of integers with only 0s and 1s in base 3 and B of integers with only 0s and 1s in base 4; resolved (under one density convention) by a DeepMind Lean-proof-search agent.