The Parabolic K-motivic Hecke Category
Jens Niklas Eberhardt, Arnaud Eteve
TL;DR
This work defines the parabolic $K$-motivic Hecke category $\mathcal{H}_{P,Q}$ in genuine equivariant $K$-theory and provides a Soergel-type description via singular $K$-theory Soergel bimodules. Under mild hypotheses, there is an equivalence between $\mathcal{H}_{P,Q}$ and chain complexes of singular SBim over the representation rings $R_P,R_Q$, linking motivic categories to algebraic $K$-theory and generalizing known cases. The spherical affine case and the connection to quantum $K$-theory Satake are highlighted, with a detailed discussion of Bott–Samelson objects, purity, and duality, and a programmatic path toward a full quantum Satake correspondence for broader types. The paper also outlines a broader program connecting these motivic Hecke categories to Langlands dual, bi-Whittaker, and coherent-sheaf pictures via weight structures and categorical Chern characters, outlining several future directions.
Abstract
We define and study the parabolic K-motivic Hecke category of a (possibly disconnected) Kac-Moody group. Our main result is a combinatorial description via singular K-theory Soergel bimodules which arise from the equivariant algebraic K-theory of parabolic Bott-Samelson resolutions. In the spherical affine case, the K-motivic Hecke category serves as one side of a conjectural quantum K-theoretic derived Satake equivalence, addressing a conjecture of Cautis-Kamnitzer.
