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 ...

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 ...

Add Yahoo as a preferred source to see more of our stories on Google. The “moving sofa problem,” a puzzle that has remained unresolved since it was introduced in 1966 and memorably illustrated in the ...

A mathematician has solved a decades-old puzzle. Jineon Baek proved a specific shape is the largest that can turn a corner.

Mathematicians aren't usually the first point of call on moving day. And really, why should they be? For nearly 60 years, they couldn't even tell you whether your fancy new three-seat sofa would make ...