25 research outputs found
Definable sets of Berkovich curves
In this article, we functorially associate definable sets to -analytic
curves, and definable maps to analytic morphisms between them, for a large
class of -analytic curves. Given a -analytic curve , our association
allows us to have definable versions of several usual notions of Berkovich
analytic geometry such as the branch emanating from a point and the residue
curve at a point of type 2. We also characterize the definable subsets of the
definable counterpart of and show that they satisfy a bijective relation
with the radial subsets of . As an application, we recover (and slightly
extend) results of Temkin concerning the radiality of the set of points with a
given prescribed multiplicity with respect to a morphism of -analytic
curves.
In the case of the analytification of an algebraic curve, our construction
can also be seen as an explicit version of Hrushovski and Loeser's theorem on
iso-definability of curves. However, our approach can also be applied to
strictly -affinoid curves and arbitrary morphisms between them, which are
currently not in the scope of their setting.Comment: 53 pages, 1 figure. v2: Section 7.2 on weakly stable fields added and
other minor changes. Final version. To appear in Journal of the Institute of
Mathematics of Jussie
Integration and Cell Decomposition in -minimal Structures
We show that the class of -constructible functions is closed
under integration for any -minimal expansion of a -adic field
. This generalizes results previously known for semi-algebraic
and sub-analytic structures. As part of the proof, we obtain a weak version of
cell decomposition and function preparation for -minimal structures, a
result which is independent of the existence of Skolem functions. %The result
is obtained from weak versions of cell decomposition and function preparation
which we prove for general -minimal structures. A direct corollary is that
Denef's results on the rationality of Poincar\'e series hold in any -minimal
expansion of a -adic field .Comment: 22 page
An example of a -minimal structure without definable Skolem functions
We show there are intermediate -minimal structures between the
semi-algebraic and sub-analytic languages which do not have definable Skolem
functions. As a consequence, by a result of Mourgues, this shows there are
-minimal structures which do not admit classical cell decomposition.Comment: 9 pages, (added missing grant acknowledgement