Identify the infinite quasisymmetric Grassmannian with the Baker–Richter loop-space model

Establish that the infinite quasisymmetric Grassmannian $Q_{\infty}$ is isomorphic to the loop space $\Omega\Sigma\mathbb{C}P^{\infty}$ as a weak $H$-group.

Background

The paper constructs an ind-variety Q∞Q_{\infty} as a direct limit of toric Richardson varieties in Grassmannians and equips it with a weak HH-group structure. Its cohomology and homology are identified, respectively, with the Hopf algebras of quasisymmetric functions QSymQSym and noncommutative symmetric functions NSymNSym.

Baker–Richter previously showed that the loop space ΩΣCP∞\Omega\Sigma\mathbb{C}P^{\infty} has cohomology QSymQSym and homology NSymNSym as Hopf algebras. The conjecture asks whether the geometric model constructed in the paper and the Baker–Richter topological model are actually isomorphic as weak HH-groups, rather than merely sharing the same Hopf-algebraic invariants. The paper later repeats this conjecture in a more detailed form as Conjecture \ref{cj:homotopic2james}.

References

Given the strong resemblance between this space and our own, we propose the following conjecture (cf. \Cref{cj:homotopic2james} and the discussion thereafter). $Q_{\infty}$ is isomorphic to $\Omega \Sigma C \mathbb{P}{\infty}$ as a weak $H$-group.

— A quasisymmetric analog of Grassmannian Schubert varieties  (2609.30257 - Gonzales et al., 24 Sep 2026) in Section 8, subsection “Relation to the literature,” immediately following the discussion of Baker–Richter’s construction