Homological stability under connected-sum stabilization

Establish whether, for a smooth closed \(2n\)-manifold \(M\), the homology groups \(H_k({M_g\langle n\rangle})\) of the spaces of homotopy self-equivalences of \(M_g=M\# g(S^n\times S^n)\) preserving the stabilized normal \(n\)-type admit a stability range for each fixed \(k>0\), depending on \(g\) and \(M\).

Background

The paper discusses stabilization of a closed even-dimensional manifold by connected sum with Sn×SnS^n\times S^n, writing Mg=M#g(Sn×Sn)M_g=M\# g(S^n\times S^n). This operation induces stabilization homomorphisms between the corresponding spaces of homotopy self-equivalences preserving the stabilized normal nn-type.

The braid relates these self-equivalence spaces to auxiliary groups associated with Postnikov sections of MgM_g. The authors ask whether the homology of the self-equivalence spaces themselves becomes stable in a range as the number gg of connected-sum factors increases.

References

Let M{2n} be a smooth, closed 2n-dimensional manifold. For a fixed k > 0, is there a stability range for the homology groups H_k({M_g n}) depending on g and M?

— Braidings of Self-Equivalences and Bordism  (2610.11110 - Hambleton et al., 8 Oct 2026) in Section 9, subsection “Stability of \({M}\) under connected sums \(M \# (S^n \times S^n)\),” Question