A Korean mathematician has solved one of geometry’s most stubborn puzzles, ending a problem that has challenged researchers for nearly 60 years and earning global recognition for a proof achieved ...

For those who have wrestled a bulky couch around a tight corner and lamented, “Will this ever get through?” mathematicians have heard your pleas. Geometry’s “moving sofa problem” asks for the largest ...

In a scene from the classic sitcom, "Friends," the characters Ross, Rachel and Chandler struggle to heft a new couch up the stairs of their apartment building. As they try to get the sofa around the ...