ScalingStacks

Remark 6.8. Note that we have the equivalences

Stab⁡(Pre​((Cat∞perf)ω)∗)\displaystyle\Stab(\mathrm{Pre}((\Cat_{\infty}^{\perf})^{\omega})_{*}) =Stab(Fun(((Cat∞perf)ω)op,𝒯∞∗))\displaystyle=\Stab(\mathrm{Fun}(((\Cat_{\infty}^{\perf})^{\omega})^{\op},{\mathcal{T}}_{\infty*}))
≃Fun(((Cat∞perf)ω)op,Stab(𝒯∞∗)))\displaystyle\simeq\mathrm{Fun}(((\Cat_{\infty}^{\perf})^{\omega})^{\op},\Stab({\mathcal{T}}_{\infty*})))
≃Fun⁡(((Cat∞perf)ω)op,𝒮∞),\displaystyle\simeq\mathrm{Fun}(((\Cat_{\infty}^{\perf})^{\omega})^{\op},{\mathcal{S}}_{\infty}),

the last of which follows from  [53, 1.4.4.11]. Therefore, defining

Pre𝒮∞​((Cat∞perf)ω)=Fun⁡(((Cat∞perf)ω)op,𝒮∞)\mathrm{Pre}_{{\mathcal{S}}_{\infty}}((\Cat_{\infty}^{\perf})^{\omega})=\mathrm{Fun}(((\Cat_{\infty}^{\perf})^{\omega})^{\op},{\mathcal{S}}_{\infty})

and writing

ψ:Cat∞perf⟶Pre𝒮∞​((Cat∞perf)ω)\psi\colon\Cat_{\infty}^{\perf}\longrightarrow\mathrm{Pre}_{{\mathcal{S}}_{\infty}}((\Cat_{\infty}^{\perf})^{\omega})

for the natural functor, we see that ℳadd{\mathcal{M}}_{\mathrm{add}} can alternately be described as the localization of Pre𝒮∞​((Cat∞perf)ω)\mathrm{Pre}_{{\mathcal{S}}_{\infty}}((\Cat_{\infty}^{\perf})^{\omega}) with respect to the set of maps

(6.9) ψ⁡(𝒞)/ψ⁡(𝒜)⟶ψ⁡(ℬ),\psi({\mathcal{C}})/\psi({\mathcal{A}})\mathchoice{\longrightarrow}{\rightarrow}{\rightarrow}{\rightarrow}\psi({\mathcal{B}})\,,

where 𝒜→𝒞→ℬ{\mathcal{A}}\mathchoice{\longrightarrow}{\rightarrow}{\rightarrow}{\rightarrow}{\mathcal{C}}\mathchoice{\longrightarrow}{\rightarrow}{\rightarrow}{\rightarrow}{\mathcal{B}} is a split-exact sequence in ℰ{\mathcal{E}}.

Original mathematics by the credited authors. Source collection and HTML conversion remain in progress.

Andrew J. Blumberg, David Gepner, Goncalo Tabuada

Original source: arXiv:1001.2282v4