Gui-Qiang G. Chen is awarded the Pólya Prize for his deep research into nonlinear partial differential equations, and in particular his rigorous theoretical analysis of the equations of gas dynamics, especially those involving transonic flows.

In this case study I report on a collaboration with Mo Dick Wong (Durham University), in the area of analytic and probabilistic number theory. We studied questions on a random model for the Möbius $\mu$ function. This function is one of the most elusive functions in number theory, and encodes deep questions on primes. Let's define it properly.