Korean Mathematician Cracks the 60-Year Moving Sofa Puzzle Using Pure Logic
Baek Jin-eon, a Korean mathematician, has resolved the long-standing moving sofa problem by proving that Gerver’s 2.2195-square-meter sofa is the maximal shape that can pass around a right-angle turn in a 1-meter-wide hallway, using only rigorous logical reasoning and no computer assistance. His 119-page proof, published as an arXiv preprint in 2024 and now under review at the Annals of Mathematics, marks a rare computer-free resolution of a six-decade-old puzzle; Scientific American named it one of the top mathematical advances of 2025.
