Mathematicians—Including MATH+ Member Alexander I. Bobenko (TU Berlin)—Solve Decades-Old Geometry Problem
Researchers have overturned a 150-year-old rule in classical geometry, originally proposed by Pierre Ossian Bonnet, which claimed a surface is uniquely determined by its metric and mean curvature. They constructed two distinct donut-shaped surfaces sharing both properties, creating the first compact ‘Bonnet pair’ and disproving