Regularity of almost minimizers for the parabolic thin obstacle problem

Abstract: In this paper, we study almost minimizers for the parabolic thin obstacle (or Signorini) problem with zero obstacle. We establish their $H^{\sigma,\sigma/2}$-regularity for every $0<\sigma<1$, as well as $H^{\beta,\beta/2}$-regularity of their spatial gradients on the either side of the thin space for some $0<\beta<1$. A similar result is also obtained for almost minimizers for the Signorini problem with variable H\"{o}lder coefficients.