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La classe fondamentale d’une variété algébrique engendre le $${\mathcal D}$$-module qui calcule sa cohomologie d’intersection. (D’après Masaki Kashiwara). (French) Zbl 0568.14010
Systèmes différentielles et singularités, Colloq. Luminy/France 1983, Astérisque 130, 260-271 (1985).
[For the entire collection see Zbl 0559.00004.]
Let X be a complex algebraic variety, $${\mathcal D}_ X$$ the sheaf of differential operators on X, and Y a hypersurface defined by $$F(x)=0$$. Put $${\mathcal L}(Y,X)$$ the $${\mathcal D}_ X$$-submodule in $${\mathcal H}^ 1_ Y({\mathcal O})$$ corresponding to the intersection complex $$i_*IC_ Y^{\bullet}$$ by the Riemann-Hilbert correspondence DR. If $$\xi$$ is a vector field on X such that $$\xi$$ (F) does not vanish on Y, then the cohomology class [$$\xi$$ (F)/F] in $$H_ Y^ 1({\mathcal O}_ X)$$ is a generator of $${\mathcal L}(Y,X)$$. This is the first version of a theorem obtained by Kashiwara (in a letter dated 16 May 1983 from Kashiwara to the author). In this paper, the author reports on the generalized version of the theorem to the case that Y is an algebraic subvariety of X of codimension d. Under some suitable conditions, Kashiwara defined $$C_{Y| X}$$ as a fundamental class of $$H^ d_ Y(X,\Omega^ d_ X)$$, and proved that $$\Omega^ d_ X\otimes_{{\mathcal O}_ X}{\mathcal L}(Y,X)\subset \Omega^ d_ X\otimes_{{\mathcal O}_ X}{\mathcal H}^ d_ Y({\mathcal O}_ X)={\mathcal H}^ d_ X(\Omega^ d_ X)$$. As a corollary, it is proved that $$\xi C_{Y| X}$$ generates $${\mathcal L}(,Y)$$ as a $${\mathcal D}_ X$$-module.
Reviewer: M.Muro

##### MSC:
 14F10 Differentials and other special sheaves; D-modules; Bernstein-Sato ideals and polynomials 14C17 Intersection theory, characteristic classes, intersection multiplicities in algebraic geometry 58J10 Differential complexes 58A10 Differential forms in global analysis 58A12 de Rham theory in global analysis 32K15 Differentiable functions on analytic spaces, differentiable spaces
##### Keywords:
sheaf of differential operators; intersection complex
Zbl 0559.00004