Non-representable six-functor formalisms

Abstract

In this article, we study the properties of motivic homotopy category ${\mathcal{S}\mathcal{H}}_{\mathrm{ext}}(\mathcal{X})$ developed by Chowdhury and Khan-Ravi for $\mathcal{X}$ a Nis-loc Stack. In particular, we compare the above construction with Voevodsky's original construction using NisLoc topology. Using the techniques developed by Liu-Zheng and Mann's notion of $\infty$-category of correspondences and abstract six-functor formalisms, we also extend the exceptional functors and extend properties like projection formula, base change and purity to the non-representable situation.

Second version with some details on the extensions to higher derived stacks. Comments are welcome!