Non-representable six-functor formalisms

TL;DR

This paper explores the properties of a motivic homotopy category for Nis-loc stacks, compares different constructions, and extends six-functor formalism properties to non-representable cases using advanced categorical techniques.

Contribution

It introduces an extension of six-functor formalism to non-representable contexts and compares motivic homotopy categories for Nis-loc stacks with classical constructions.

Findings

Extended exceptional functors to non-representable cases

Proved projection formula, base change, and purity in new settings

Compared different motivic homotopy category constructions

Abstract

In this article, we study the properties of motivic homotopy category $\mathcal{SH}_{\operatorname{ext}}(\mathcal{X})$ 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.