Baek Jin-eon, a doctor at the Korea Institute for Advanced Study’s Hur Joon-yi Mathematics Institute, has theoretically solved the “moving sofa problem,” a mathematical conundrum that has remained unsolved for nearly 60 years. According to the mathematics community on the 4th, the American scientific journal “Scientific American” selected Dr. Baek Jin-eon’s (31) research as one of the top 10 mathematical innovations of 2025. The problem, introduced by Canadian mathematician Leo Moser in 1966, involves finding the shape with the maximum area that can pass through a corridor of width 1. While intuitive, it is extremely mathematically challenging, gaining notoriety by being included in American math textbooks.
Previously, various shapes were proposed without theoretical proof of an optimal solution. In 1968, British mathematician John Hammersley suggested a sofa with an area of about 2.2074, and in 1992, American mathematician Joseph Gerver proposed “Gerver’s sofa” with 18 curves considering contact order with the wall, having an area of 2.2195, but without proof it was optimal.
After seven years of research, Dr. Baek published a 119-page paper on the preprint site “arXiv” at the end of last year, proving for the first time that no larger sofa than Gerver’s could exist. While previous studies focused on narrowing the upper limit through computational calculations, this research is significant for proving the optimal model solely through logical reasoning.
Dr. Baek encountered the problem during his time as a specialist researcher at the National Institute for Mathematical Sciences and persistently pursued a solution during his Ph.D. at the University of Michigan in the U.S. He described the process as repeatedly breaking hope and drawing new ideas from the ashes. The research has been submitted to “Annals of Mathematics,” the most prestigious journal in the field, and is currently undergoing verification.
Having solved the problem at 29, he was selected as a “Hur Joon-yi Fellow,” supporting young mathematicians under 39 for an extended period, and continues his research in combinatorial geometry and optimization problems. Dr. Baek expressed hope for comprehensive evaluations of whether fundamental problems are solved, rather than quickly checking the number of papers or short-term achievements.