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 σ≥1; then we prove the blow
up of the solution for every real p∈]1,1+2[ and non--negative
non--trivial initial data.Comment: some typos are corrected and some references are adde