A long-standing mathematical puzzle known as the “sofa problem,” posed in 1966 by Austrian-Canadian mathematician Leo Moser, may have finally been solved. The problem involves determining the maximum area of a single, planar shape that can navigate a right-angled corner in a hallway of unit width. This question, despite its seemingly simple premise, has confounded mathematicians for over half a century.
Jineon Baek, a postdoctoral researcher in mathematics at Yonsei University in South Korea, has reportedly proposed a solution. According to a study shared on the preprint website ArXiv on December 2, Baek demonstrated that the maximum area of the hypothetical sofa is 2.2195 units. This value refines the previously established range of 2.2195 to 2.37 units. While the proof awaits peer review, experts are expected to verify its accuracy.
Origins and Prior Developments
The problem was initially conceptualised by Leo Moser and progress was made in 1992 when Joseph Gerver, an emeritus professor at Rutgers University, proposed a U-shaped solution comprising 18 curves. Gerver’s calculations suggested the lower bound of 2.2195 units for the sofa’s area. Disputes persisted over whether a larger sofa could exist, with a 2018 computer-assisted analysis suggesting an upper bound of 2.37 units.
Key Insights from Baek’s Proof
Baek’s findings reportedly confirm that Gerver’s solution represents the optimal configuration. By meticulously analyzing the geometry and movement of the shape, Baek demonstrated that the U-shaped design could achieve the maximum possible area for navigating the corner.
While the study has yet to be published in a peer-reviewed journal, the mathematical community has shown significant interest. Images of the “Gerver sofa” circulated on social media following Baek’s announcement, sparking discussions about the implications of this long-awaited resolution.
This breakthrough is anticipated to close the chapter on one of mathematics’ enduring conundrums, pending independent verification of Baek’s work.