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ЖУРНАЛЫ // Алгебра и анализ // Архив

Алгебра и анализ, 2020, том 32, выпуск 3, страницы 39–64 (Mi aa1699)

Статьи

Almost everywhere regularity for the free boundary of the $p$-harmonic obstacle problem $p>2$

J. Andersson

Institutionen för matematik KTH, 100 44 Stockholm, Sweden

Аннотация: Let $u$ be a solution to the normalized $p$-harmonic obstacle problem with $p>2$. That is, $u\in W^{1,p}(B_1(0))$, $2<p<\infty$, $u\ge 0$ and
$$ \mathrm{div}\,( |\nabla u|^{p-2}\nabla u)=\chi_{\{u>0\}}\textrm{ in }B_1(0) $$
where $u(x)\ge 0$ and $\chi_A$ is the characteristic function of the set $A$. The main result is that for almost every free boundary point with respect to the $(n-1)$-Hausdorff measure, there is a neighborhood where the free boundary is a $C^{1,\beta}$-graph. That is, for $\mathcal{H}^{n-1}$-a.e. point $x^0\in \partial \{u>0\}\cap B_1(0)$ there is an $r>0$ such that $B_r(x^0)\cap \partial \{u>0\}\in C^{1,\beta}$.

Ключевые слова: $p$-Laplace operator, blow-up, Carleson measure Hausdorff measure.

Поступила в редакцию: 18.12.2018

Язык публикации: английский


 Англоязычная версия: St. Petersburg Mathematical Journal, 2021, 32:3, 415–433


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