Fiber bundles and regular approximation of codimension-one cycles.

We derive an approximation of codimension-one integral cycles (and cycles modulo p) in a compact riemannian manifolds by means of piecewise regular cycles: we obtain both flat convergence, and convergence of the masses. The theorem is proved by using suitable principal bundles with discrete group. As a byproduct, we give an alternative proof of the main results in [BO1], [BO2], which does not use the regularity theory for homology minimizers in a riemannian manifold. This gives also a result of G-convergence