arXiv subjects
Publications and source records attributed to Amalie Høgenhaven.
We compute the component group of the derived $G$-geometric fixed points of the real topological Hochschild homology of a ring with anti-involution, where $G$ denotes the Galois group Gal($\mathbb{C}$/$\mathbb{R}$) of order 2.
In recent work, Hess and Shipley defined a theory of topological coHochschild homology (coTHH) for coalgebras. In this paper we develop computational tools to study this new theory. In particular, we prove a Hochschild-Kostant-Rosenberg type theorem in the cofree case for differential graded coalgebras. We also develop a coBökstedt spectral sequence to compute the homology of coTHH for coalgebra spectra. We use a coalgebra structure on this spectral sequence to produce several computations.
We compute the $G$-equivariant homotopy type of the real topological cyclic homology of spherical group rings with anti-involution induced by taking inverses in the group, where $G$ denotes the group $Gal(\mathbb{C}/\mathbb{R})$. The real topological Hochschild homology of a spherical group ring $\mathbb{S}[Γ]$, with anti-involution as described, is an $O(2)$-cyclotomic spectrum and we construct a map commuting with the cyclotomic structures from the $O(2)$-equivariant suspension spectrum of the dihedral bar construction on $Γ$ to the real topological Hochschild homology of $\mathbb{S}[Γ]$, which induce isomorphisms on $C_{p^n}$- and $D_{p^n}$-homotopy groups for all $n\in \mathbb{Z}$ and all primes $p$. Here $C_{p^n}$ is the cyclic group of order $p^n$ and $D_{p^n}$ is the dihedral group of order $2p^n$. Finally, we compute the $G$-equivariant homotopy type of the real topological cyclic homology of $\mathbb{S}[Γ]$ at a prime $p$.