A note on Deligne's formula

Abstract

Let $R$ denote a Noetherian ring and an ideal $J\subset R$ with $U=\mathrm{SpecR}\setminus V(J)$. For an $R$-module $M$ there is an isomorphism $\Gamma (U,\tilde{M})\cong \underrightarrow{\lim }{\mathrm{Hom}}_R(J^n,M)$ known as Deligne's formula (see [R. Hartshorne: Algebraic Geometry, Springer, 1983] and Deligne's Appendix in [R. Hartshorne: Residues and Duality, Lecture Notes in Math. 20, Springer,1966] ). We extend the isomorphism for any $R$-module $M$ in the non-Noetherian case of $R$ and $J=(x_1,\dots ,x_k)$ a certain finitely generated ideal. Moreover, we recall a corresponding sheaf construction.

To appear in J. Pure Apple. Algebra