Functors given by kernels, adjunctions and duality

TL;DR

This paper explores the relationships between kernels, adjunctions, and duality in the context of D-modules on schemes and stacks, revealing how dual objects relate to original kernels and extending the theory to Artin stacks.

Contribution

It establishes a connection between the kernel defining a functor and its right adjoint via Verdier duality, generalizing from schemes to Artin stacks.

Findings

P is related to the Verdier dual of Q for schemes.

Extension of duality relations to Artin stacks.

Provides a framework for understanding adjunctions via duality.

Abstract

Let X_1 and X_2 be schemes of finite type over a field of characteristic 0. Let Q be an object in the category D-mod(X_1\times X_2) and consider the functor F:D-mod(X_1)->Dmod(X_2) defined by Q. Assume that F admits a right adjoint also defined by an object P in D-mod(X_1\times X_2). The question that we pose and answer in this paper is how P is related to the Verdier dual of Q. We subsequently generalize this question to the case when X_1 and X_2 are no longer schemes but Artin stacks, where the situation becomes much more interesting.