Parabolic differential equations with rough data Herbert Koch (Bonn) It is an important insight from harmonic analysis that maximal functions, square functions and Carleson measures are useful objects to understand and describe properties of functions, operators and differential equations. I report on joint work with Tobias Lamm on applications of these concepts to nonlinear parabolic equations. Instances are: 1) Wellposedness for the Navier-Stokes equations for initial data whose components are the divergence of BMO vector fields. 2) The solution of the Kato square root conjecture. 3) The harmonic map heat flow with initial data in BMO by Auscher et al. 4) Lipschitz perturbations to linear fronts for porous media and thin films.