Erdos problem 90 has been resolved. While at this point more than a dozen Erdos problems have been solved using AI, most are considered trivial. But problem 90 is different. It went unsolved for 80 years, resisting the attempts of generations of mathematicians despite its simple setup.
A map of general route of Zheng He’s seventh and final voyage across the Indian Ocean, from 1431 to 1433, overlaid with Ming China’s overseas depots, the Old Port Pacification Superintendency, and the sites of battles fought by Zheng He’s fleets during his expeditions. Popular memory often presents the treasure voyages as peaceful diplomatic missions, but they were also a (short-lived) project of imperial power projection.
The popular account of Zheng He describes peaceful exchange, gifts, silk, porcelain, and no conquest. But He fought a land war in Sri Lanka, captured rulers at three different stops, and established an overseas Pacification Superintendency in Sumatra. Lengthy essay on what the Ming Dynasty maritime project actually was, and how it was larger than just Zheng He.