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Topological $ΔG$ homology of rings with twisted $G$-action

Gabriel Angelini-Knoll, Mona Merling, Maximilien Péroux

Abstract

We construct topological $ΔG$-homology for rings with twisted $G$-action. Here a ring with twisted $G$-action is a common generalization of a ring with anti-involution and a ring with $G$-action. This construction recovers as special cases topological Hochschild homology (THH) of rings, with its $S^1$-action, and Real topological Hochschild homology (THR) of rings with anti-involution, with its $O(2)$-action. A new example of this construction is quaternionic topological Hochschild homology (THQ) of rings with twisted $C_4$-action, which carries a $Pin(2)$-action. We prove that THQ of a loop space with twisted $C_4$-action can be $Pin(2)$-equivariantly identified with a twisted free loop space. Other new examples of interest are topological symmetric homology and topological hyperoctrahedral homology and more generally topological twisted symmetric homology. We prove a homotopical version of results of Fiedorowicz, Ault, and Graves computing these new topological homology theories on loop spaces with twisted $G$-action. A key step of independent interest in this program is the construction of a new family of crossed simplicial groups, which correspond to operads that encode the structure of rings with twisted $G$-action.

Topological $ΔG$ homology of rings with twisted $G$-action

Abstract

We construct topological -homology for rings with twisted -action. Here a ring with twisted -action is a common generalization of a ring with anti-involution and a ring with -action. This construction recovers as special cases topological Hochschild homology (THH) of rings, with its -action, and Real topological Hochschild homology (THR) of rings with anti-involution, with its -action. A new example of this construction is quaternionic topological Hochschild homology (THQ) of rings with twisted -action, which carries a -action. We prove that THQ of a loop space with twisted -action can be -equivariantly identified with a twisted free loop space. Other new examples of interest are topological symmetric homology and topological hyperoctrahedral homology and more generally topological twisted symmetric homology. We prove a homotopical version of results of Fiedorowicz, Ault, and Graves computing these new topological homology theories on loop spaces with twisted -action. A key step of independent interest in this program is the construction of a new family of crossed simplicial groups, which correspond to operads that encode the structure of rings with twisted -action.
Paper Structure (26 sections, 42 theorems, 222 equations, 5 figures)

This paper contains 26 sections, 42 theorems, 222 equations, 5 figures.

Key Result

Theorem A

For a self-dual crossed simplicial group $\Delta \mathbf{G}$, there is an associated topological homology $\mathop{\mathrm{\mathrm{TH}\mathbf{G}}}\nolimits(R)$ which carries a $|\mathbf{G}_{\,\begin{picture}(-1,1)(0.5,-1)\circle*{1.8}\end{picture}\space}|$-action, whose input is a ring spectrum $R$

Figures (5)

  • Figure 1: Table of common crossed simplicial groups
  • Figure 2: Example in $\Delta \mathbf{\Sigma}$ for some $\phi\colon[5]\to [3]$ and $\gamma\in \Sigma_4$.
  • Figure 3: Example in $\Delta \varphi\wr\mathbf{\Sigma}$ for some $\phi\colon[5]\to [3]$ and $\gamma\in \Sigma_4$.
  • Figure 4: The permutation $\sigma_4$ induced by $\gamma_1$ and $\sigma_2$ in $\Delta \varphi\wr \mathbf{\Sigma}$
  • Figure 5: Various crossed simplicial groups and their topological homology

Theorems & Definitions (153)

  • Theorem A
  • Theorem B: \ref{['thm: main computation']}
  • Theorem C
  • Theorem D: \ref{['thm: topological positive hyperoctahedral homology']}
  • Definition 2.1
  • Remark 2.2
  • Proposition 2.3: FL91
  • Example 2.4
  • Lemma 2.5
  • proof
  • ...and 143 more