The talk **Localization of $W^{-1,q}$ norm for local a posteriori efficiency**, by Jan Blechta, will be held on Monday April 4, 2016 at 9:00 in room **K6**.

**Abstract**

We show how to localize dual norms of bounded linear functionals on the Sobolev space $W_0^{1,p}(\Omega)$. The only condition is that the functional in question vanishes over locally supported test functions from $W_0^{1,p}(\Omega)$ which form a partition of unity in $\Omega$, apart from close to the boundary $\partial\Omega$. The results allow in particular to establish local efficiency and robustness for a posteriori analysis of nonlinear partial differential equations of divergence form.