Geometric Auslander criterion for openness of an algebraic morphism
Algebraic Geometry
2017-09-29 v2
Abstract
We give an effective criterion for openness of a morphism of schemes of finite type over a field: Over a normal base of dimension n, failure of openness is detected by a vertical component in the n'th fibred power of the morphism. This is a topological analogue of a criterion for flatness that originates with Auslander.
Cite
@article{arxiv.1006.1872,
title = {Geometric Auslander criterion for openness of an algebraic morphism},
author = {Janusz Adamus and Edward Bierstone and Pierre D. Milman},
journal= {arXiv preprint arXiv:1006.1872},
year = {2017}
}
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