Extension of functors for algebras of formal deformation

Abstract

Suppose we are given complex manifolds $X$ and $Y$ together with substacks $\mathcal{S}$ and ${\mathcal{S}}^{\prime }$ of modules over algebras of formal deformation $\mathcal{A}$ on $X$ and ${\mathcal{A}}^{\prime }$ on $Y$, respectively. Suppose also we are given a functor $\Phi$ from the category of open subsets of $X$ to the category of open subsets of $Y$ together with a functor $F$ of prestacks from $\mathcal{S}$ to ${\mathcal{S}}^{\prime }\circ \Phi$. Then we give conditions for the existence of a canonical functor, extension of $F$ to the category of coherent ${\sha}$-modules such that the cohomology associated to the action of the formal parameter $\hslash$ takes values in $\mathcal{S}$. We give an explicit construction and prove that when the initial functor $F$ is exact on each open subset, so is its extension. Our construction permits to extend the functors of inverse image, Fourier transform, specialization and microlocalization, nearby and vanishing cycles in the framework of $\shd[[\hbar]]$-modules. We also obtain a Cauchy-Kowalewskaia-Kashiwara theorem in the non-characteristic case as well as comparison theorems for regular holonomic $\shd[[\hbar]]$-modules and a coherency criterion for proper direct images of good $\shd[[\hbar]]$-modules.

Typos corrected; accepted in Glasgow Mathematical Journal