A priori estimate for a family of semi-linear elliptic equations with critical nonlinearity

Abstract

We consider positive solutions of $\Delta u-\mu u+K{u}^{\frac{n+2}{n-2}}=0$ on $B_1$ ($n\ge 5$) where $\mu$ and $K>0$ are smooth functions on $B_1$. If $K$ is very sub-harmonic at each critical point of $K$ in $B_{2/3}$ and the maximum of $u$ in ${\bar{B}}_{1/3}$ is comparable to its maximum over ${\bar{B}}_1$, then all positive solutions are uniformly bounded on ${\bar{B}}_{1/3}$. As an application, a priori estimate for solutions of equations defined on ${\mathbb{S}}^n$ is derived.

26 pages