On the fundamental class of an essentially smooth scheme-map
arXiv:1501.00954 · doi:10.14231/AG-2018-005
Abstract
Let f: X -> Z be a separated essentially-finite-type flat map of noetherian schemes, and δ: X --> X \times_Z X the diagonal map. The fundamental class C_f (globalizing residues) is a map from the relative Hochschild functor Lδ^*δ_* f^* to the relative dualizing functor f^! A compatibility between this C_f and derived tensor product is shown. The main result is that, in a suitable sense, C_f generalizes Verdier's classical isomorphism for smooth f with fibers of dimension d, an isomorphism that binds f^! to relative d-forms.
Minor corrections. 31 pages. To appear in Algebraic Geometry