Čech cohomology and covering dimension for topological spaces
We prove that Alexander-Spanier cohomology with coefficients in a topologicalAbelian group G is isomorphic to the group of isomorphism classes of principal bundles with certain Abelian structure groups. The result holds if either X is a CW-space and G arbitrary or if X is metrizable or compact Hausdorff and G an ANR.
A characterisation of trivial 1-cohomology, in terms of some connectedness condition, is presented for a broad class of metric spaces.