On the singular set of the parabolic obstacle problem (Q858698)

This paper is devoted to regularity results and geometric properties of the singular set of the following parabolic obstacle problem \[ \Delta u-u_t=[1+f]I_{\{ u>0\}},\quad u\geq 0 \] where \(I_{\{ u>0\}}\) is the characteristic function of the set \(\{ u>0\}\). It is possible to reduce the parabolic obstacle problem with variable coefficients to this problem by a suitable transformation.