Metric cohomology of Z^n

We develop a set of tools necessary to compute coarse sheaf cohomology of $\mathbb R^n$ . One key ingredient is the cohomology of $\mathbb R_{\ge0}$ . Another one is a version of homotopy theory on coarse metric spaces. We show our cohomology theory is a coarse homotopy invariant. Using this we construct a Leray cover of $\mathbb R^n$ , the Cech cohomology of which gives us the desired result.