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Title
Irrationality of rapidly converging series: A problem of Erdős and Graham
KIAS Author
Kim, Sang-hyun
Journal
BULLETIN OF THE LONDON MATHEMATICAL SOCIETY, 2026
Archive
Abstract
Answering a question of Erd & odblac;s and Graham, we show that the double-exponential growth condition for a strictly increasing sequence of positive integers is sufficient for the series to have an irrational sum; here denotes the golden ratio. We also provide a positive generalization to , and a negative result showing that some of these instances are essentially optimal. The original problem was autonomously solved by the AI agent Aletheia, powered by Gemini Deep Think, while the remaining material is largely a product of human-AI interactions.