Blow Up for the Semilinear Wave Equation in Schwarzschild Metric
  We study the semilinear wave equation in Schwarzschild metric (3+1 dimensional space--time). First, we establish that the problem is locally well--posed in $\cs H^\sigma$ for any $\sigma \geq 1$; then we prove the blow up of the solution for every real $p \in ]1,1+\sqrt{2}[$ and non--negative non--trivial initial data. 
Davide Catania, Vladimir Georgiev