Quantum wreath products and Schur--Weyl duality II

Abstract: We solve the conjecture of Ginzburg, Guay, Opdam, and Rouquier regarding constructing highest weight covers of the Hecke algebra, in type D. Departing from existing Cherednik-algebra techniques, our new theory is based on an interplay between a natural generalization of dual Specht modules, and a Grothendieck spectral sequence for finite-dimensional algebras that admit (inverse) Schur functors. While the main result is regarding type $D_{2m} = G(2,2,2m)$, partial results are proved along the way for complex reflection groups $G(d,d,dm)$ and $G(m,1,d)$. Our framework should extend to all Weyl groups and general $G(m,r,n)$. A key ingredient in our methods is a unifying construction of modules over quantum wreath products, in terms of parabolic inductions on tensor products of the ``wreath modules'' introduced in the article. This construction simultaneously recovers (and hence provides a more transparent realization of) important families of modules in the literature, including simple modules over the Ariki-Koike algebra, (anti)spherical modules and the Kashiwara-Miwa-Stern modules over the affine Hecke algebra, as well as the Specht and simple modules over the Hu algebra.