On the ring of cooperations for real hermitian K-theory
Abstract
Let kq denote the very effective cover of the motivic Hermitian K-theory spectrum. We analyze the ring of cooperations in the stable motivic homotopy category , giving a full description in terms of Brown--Gitler comodules. To do this, we decompose the -page of the motivic Adams spectral sequence and show that it must collapse. The description of the -page is accomplished by a series of algebraic Atiyah--Hirzebruch spectral sequences which converge to the summands of the -page. Along the way, we prove a splitting result for the very effective symplectic K-theory ksp over any base field of characteristic not two.
Keywords
Cite
@article{arxiv.2506.16672,
title = {On the ring of cooperations for real hermitian K-theory},
author = {Jackson Morris},
journal= {arXiv preprint arXiv:2506.16672},
year = {2026}
}
Comments
65 pages, 38 figures. Comments welcome! v2: added section 8.3, other changes based on referee report. v3: Final version, to appear in Annals of K-theory. Margin size change, figures now vector files