  Let L be a p-adic local field and g a finite dimensional Lie algebra over L.
We show that its hyperenveloping algebra F(g) is a stably flat completion of
its universal enveloping algebra. As a consequence the relative cohomology for
the locally convex algebra F(g) coincides with the underlying Lie algebra
cohomology. Final version. Some minor items corrected. Appeared in Journal of
Algebra (2010).
