Topological CoHochschild Homology and Thom Spectra
Jiaxi Zha
TL;DR
The paper develops a framework for topological coHochschild homology with Thom-spectrum coefficients, focusing on Thom spectra Th(f) over simply connected spaces X and input data f: X → Pic(R). It establishes a duality-like result coTHH^R(Th f; R[X]) ≃ Th f ⊗ Σ^{∞}_+ ΩX and constructs a skeleton filtration whose associated graded pieces are controlled by the loop space ΩX, reducing computations to coTHH on group-like spaces. A geometric description expresses coTHH^R(Th f;R[X]) as a colimit over Δ^{op} of coTHH^R(R[G^n]) with G = ΩX, and orientation-compatible base-change results yield spectral sequences for A-homology in favorable cases. Together, these results provide concrete tools for calculating coTHH in Thom-spectra contexts and illuminate the interplay between Thom constructions, comodule structures, and loop-space data.
Abstract
For an $\E$-ring spectrum $R$ and a map $f:X\to Pic(R)$ of spaces, the Thom spectrum $\T f$ is a comodule over $R\otimes\Si X$. In this parper we study the topological coHochschild homology of $R\otimes\Si X$ with coefficient $\T f$. More concretely, for a simply connected space $X$, we will give a filtration on $\mathrm{coTHH}^R(\T f;R\otimes\Si X)$ via the cellular structure of $X$. Furthermore, we will reduce the computation of $\mathrm{coTHH}^R(\T f;R\otimes\Si X)$ to that of $\mathrm{coTHH}^R(R\otimes\Si G)$ for some group-like $\mathbb{E}_1$-spaces. Finally, we will use these results to study properties of $\mathrm{coTHH}(\T f;R\otimes\Si X)$.
