Sobolev spaces on non-Lipschitz domains Andrea Moiola (Reading) Joint work with Simon Chandler-Wilde (Reading) and David Hewett (UCL) Recent studies into scattering by fractal screens has motivated investigations into the properties of fractional Sobolev spaces (the classical Bessel potential spaces) on non-Lipschitz domains. We wanted to investigate the extent to which the properties of these spaces, and the relations between them, that hold in the well-studied case of a Lipschitz open set, generalise to non-Lipschitz cases. Our motivation is to develop the functional analytic framework in which to formulate and analyse integral equations on non-Lipschitz sets.