Decades-old problem in classical geometry solved: First compact pair of bonnets found

For over 150 years, a rule of thumb dating back to the French mathematician Pierre Ossian Bonnet has been accepted in surface theory: If the metric and mean curvature of a compact surface are known at every point, then the surface can be uniquely determined. However, a team of three mathematicians from the Technical University of Munich (TUM), the Technical University of Berlin and North Carolina State University have now managed to disprove this recognized rule.