Lemma 33.16.6. Let f : X \to Y be a morphism of schemes over a base scheme S. Let x \in X be a point. Set y = f(x). If \kappa (y) = \kappa (x), then f induces a natural linear map
\text{d}f : T_{X/S, x} \longrightarrow T_{Y/S, y}
which is dual to the linear map \Omega _{Y/S, y} \otimes \kappa (y) \to \Omega _{X/S, x} via the identifications of Lemma 33.16.4.
Comments (3)
Comment #3268 by Dario Weißmann on
Comment #3271 by Dario Weißmann on
Comment #3363 by Johan on