A motivic filtration on the topological cyclic homology of commutative ring spectra

Abstract

For a prime number $p$ and a $p$-quasisyntomic commutative ring $R$, Bhatt–Morrow–Scholze defined motivic filtrations on the $p$-completions of $\mathrm{THH}(R)$, $\mathrm{TC}^-(R)$,$\mathrm{TP}(R)$, and $\mathrm{TC}(R)$, with the associated graded objects or $\mathrm{TP}(R)$ and $\mathrm{TC}(R)$ recovering the prismatic and syntomic cohomology of $R$, respectively. We give an alternate construction of thesee filtrations that applies also when $R$ is a well-behaved commutative ring spectrum; for example, we can take $R$ to be $\mathbb{S}$, $\mathrm{MU}$, $\mathrm{ku}$, $\mathrm{ko}$, or $\mathrm{tmf}$. We compute the $\mathrm{mod}(p,v_1)$ syntomic cohomology of the Adams summand $\ell$ and observe that, when $p\ge 3$, the motivic spectral sequenc for $V(1)_\ast \mathrm{TC}(\ell)$ collapses at the $\mathrm{E}_2$-page.

Authors

Jeremy Hahn

Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA, 02142

Arpon Raksit

Department of Mathematics, Massachusetts Institute of Technology, Cambridge, MA, 02142

Dylan Wilson

Department of Mathematics, West Virginia University, Morgantown, WV 26505