Relative completions of linear groups over Z[t] and Z[t,t⁻¹]

الأصل · EN

We compute the completion of the groups SLₙ(Z[t]) and SLₙ(Z[t,t⁻¹]) relative to the obvious homomorphisms to SLₙ(Q); this is a generalization of the classical Malcev completion. We also make partial computations of the rational second cohomology of these groups.