Starshape of the superlevel sets of solutions to equations involving the fractional Laplacian in starshaped rings

Sven Jarohs, Tadeusz Kulczycki, Paolo Salani

In the present work we study solutions of the problem $-(-\Delta {)}^{\alpha /2}u=f(x,u)$ in $D_0\setminus {\overline{D}}_1$, with exterior conditions $u=0$ in $R^N\setminus D_0$ and $u=1$…