Namely, the assumption implies that for every prime p, one has induced isomorphisms H∗>n(BH;Z/p) → H∗>n(BG;Z/p) and thus, by applying the “reconstruction functor”, isomorphisms H∗(BH;Z/p)→ H∗(BG;Z/p). Since BG and BH are spaces of finite type, it follows that the induced map H∗(BH;Z)→ H∗(BG;Z) is an isomorphism too. Thus, by Jackowski [6] and Minami [10], ρ is an isomorphism of Lie groups. In s...