20K10 2 Ulm factors 2 Ulm subgroups 2 almost \(\omega_1\)-\(p^{\omega+n}\)-projective groups 2 almost \(p^{\omega+n}\)-projective groups 2 countable subgroups nice subgroups 2 strongly almost \(\omega_1\)-\(p^{\omega+n}\)-projective groups 2