In this paper we analyze the singular set in the Stefan problem and prove the
following results:
- The singular set has parabolic Hausdorff dimension at most n−1.
- The solution admits a C∞-expansion at all singular points, up to a
set of parabolic Hausdorff dimension at most n−2.
- In R3, the free boundary is smooth for almost every time t,
and the set of singular times S⊂R has Hausdorff
dimension at most 1/2.
These results provide us with a refined understanding of the Stefan problem’s
singularities and answer some long-standing open questions in the field.