Emil Wiedemann

Since the famous work of V. Scheffer about 20 years ago, it has been known that the Cauchy problem for the incompressible Euler equations has non-unique weak solutions. Recently, De Lellis and Szekelyhidi demonstrated that this phenomenon can be...

It is well-known that variational problems may fail to have a classical minimiser if the integrand is not convex. In the 1930s, L. C. Young suggested a relaxation of such problems, where the minimising map is allowed to be measure-valued. In physical...