Baek Jin-eon Solves 60-Year Moving Sofa Problem With 119-Page Proof

2 articles · Updated · artthreat.net · Jun 4

31-year-old Korean mathematician Baek Jin-eon proved the optimal shape for the moving sofa problem, a geometry puzzle posed in 1966 about the largest rigid object that can turn a 1-meter-wide right angle.
His 119-page argument shows Joseph Gerver’s 1992 shape with area about 2.2195 square meters is the maximum possible, settling a question that had resisted proof for nearly six decades.
Baek spent 7 years on the problem, starting at South Korea’s National Institute for Mathematical Sciences and continuing through his PhD at the University of Michigan and postdoctoral work at Yonsei University.
The result was posted to arXiv in late 2024 and is under review at Annals of Mathematics; Scientific American later named it one of 2025’s 10 biggest mathematical advances.
Now at the Korean Institute of Advanced Study’s June E Huh Center, Baek says the breakthrough closes one classic optimization puzzle while pointing to broader work in combinatorial geometry.