“…To mention an example, there exist bounded C 1 domains Ω ⊆ R d such that if we define S(Ω) to be the set of all solutions to the Poisson equation with zero Dirichlet boundary conditions and right hand sides f ∈ C ∞ (Ω), then s p (S(Ω)) = 1 + 1/p, see Section 3.1 for details. Similar results for (stochastic) evolution equations can be found, e.g., in [20,25]. At the same time, we know that the solution to most of the equations in the aforementioned references may have higher regularity α > s p in the scale ( * ), see, e.g., [3,5,7,8,10,11,12,15,16,21].…”