In April 2026, OpenAI's GPT-5.4 Pro solved Erdős Problem #1196, a conjecture about primitive sets posed in 1968 by Erdős, Sárközy, and Szemerédi, completing a proof in roughly 80 minutes. The session was run by 23-year-old Liam Price and Cambridge undergraduate Kevin Barreto; the model applied Markov chain techniques via the von Mangoldt function—a connection human mathematicians had overlooked for decades. Terence Tao called the result "a meaningful contribution" that "reveals a previously undescribed connection between the anatomy of integers and Markov process theory," and Oxford mathematician Jared Lichtman described it as the first AI result at the level of Erdős's Book, as reported by Scientific American. The case is notable because the proof is genuinely novel—not a literature retrieval—and was extended by Tao into the seed of a broader theory within 24 hours.