The behavior of essential dimension under specializationArticle
Auteurs : Zinovy Reichstein ; Federico Scavia
NULL##NULL
Zinovy Reichstein;Federico Scavia
Let A be a discrete valuation ring with generic point η and closed
point s. We show that in a family of torsors over Spec(A),
the essential dimension of the torsor above s is less than or equal to the
essential dimension of the torsor above η. We give two applications of
this result, one in mixed characteristic, the other in equal characteristic.