nLab
relative dimension

Contents

For morphisms of schemes

Definition

Let f:XYf : X \to Y be a morphism locally of finite type between two schemes XX and YY. The relative dimension of ff at a point yYy \in Y is the dimension of the fiber f 1(y)f^{-1}(y). If all the nonempty fibers f 1(y)f^{-1}(y) (yYy \in Y) are purely? of the same dimension nn, then one says that ff is of relative dimension nn.

References

Though the definition does not seem to appear in EGA, there are some relevant propositions in (EGA, IV_2, 5.6):

Revised on March 23, 2013 16:59:54 by Adeel Ahmad Khan (74.107.106.124)