501 research outputs found
Existential uniform -adic integration and descent for integrability and largest poles
Since the work by Denef, -adic cell decomposition provides a
well-established method to study -adic and motivic integrals. In this paper,
we present a variant of this method that keeps track of existential
quantifiers. This enables us to deduce descent properties for -adic
integrals. In particular, we show that integrability for `existential'
functions descends from any -adic field to any -adic subfield. As an
application, we obtain that the largest pole of the Serre-Poincar\'e series can
only increase when passing to field extensions. As a side result, we prove a
relative quantifier elimination statement for Henselian valued fields of
characteristic zero that preserves existential formulas.Comment: 38 page
Motivic integration and the Grothendieck group of pseudo-finite fields
We survey our recent work on an extension of the theory of motivic
integration, called arithmetic motivic integration. We developed this theory to
understand how p-adic integrals of a very general type depend on p.Comment: 11 page
Analytic cell decomposition and analytic motivic integration
The main results of this paper are a Cell Decomposition Theorem for Henselian
valued fields with analytic structure in an analytic Denef-Pas language, and
its application to analytic motivic integrals and analytic integrals over
\FF_q((t)) of big enough characteristic. To accomplish this, we introduce a
general framework for Henselian valued fields with analytic structure, and
we investigate the structure of analytic functions in one variable, defined on
annuli over . We also prove that, after parameterization, definable analytic
functions are given by terms. The results in this paper pave the way for a
theory of \emph{analytic} motivic integration and \emph{analytic} motivic
constructible functions in the line of R. Cluckers and F. Loeser
[\emph{Fonctions constructible et int\'egration motivic I}, Comptes rendus de
l'Acad\'emie des Sciences, {\bf 339} (2004) 411 - 416]
A closedness theorem and applications in geometry of rational points over Henselian valued fields
We develop geometry of algebraic subvarieties of over arbitrary
Henselian valued fields . This is a continuation of our previous article
concerned with algebraic geometry over rank one valued fields. At the center of
our approach is again the closedness theorem that the projections are definably closed maps. It enables application
of resolution of singularities in much the same way as over locally compact
ground fields. As before, the proof of that theorem uses i.a. the local
behavior of definable functions of one variable and fiber shrinking, being a
relaxed version of curve selection. But now, to achieve the former result, we
first examine functions given by algebraic power series. All our previous
results will be established here in the general settings: several versions of
curve selection (via resolution of singularities) and of the \L{}ojasiewicz
inequality (via two instances of quantifier elimination indicated below),
extending continuous hereditarily rational functions as well as the theory of
regulous functions, sets and sheaves, including Nullstellensatz and Cartan's
theorems A and B. Two basic tools applied in this paper are quantifier
elimination for Henselian valued fields due to Pas and relative quantifier
elimination for ordered abelian groups (in a many-sorted language with
imaginary auxiliary sorts) due to Cluckers--Halupczok. Other, new applications
of the closedness theorem are piecewise continuity of definable functions,
H\"{o}lder continuity of definable functions on closed bounded subsets of
, the existence of definable retractions onto closed definable subsets
of , and a definable, non-Archimedean version of the Tietze--Urysohn
extension theorem. In a recent preprint, we established a version of the
closedness theorem over Henselian valued fields with analytic structure along
with some applications.Comment: This paper has been published in Journal of Singularities 21 (2020),
233-254. arXiv admin note: substantial text overlap with arXiv:1704.01093,
arXiv:1703.08203, arXiv:1702.0784
Cell Decomposition for semibounded p-adic sets
We study a reduct L\ast of the ring language where multiplication is
restricted to a neighbourhood of zero. The language is chosen such that for
p-adically closed fields K, the L\ast-definable subsets of K coincide with the
semi-algebraic subsets of K. Hence structures (K,L\ast) can be seen as the
p-adic counterpart of the o-minimal structure of semibounded sets. We show that
in this language, p-adically closed fields admit cell decomposition, using
cells similar to p-adic semi-algebraic cells. From this we can derive
quantifier-elimination, and give a characterization of definable functions. In
particular, we conclude that multi- plication can only be defined on bounded
sets, and we consider the existence of definable Skolem functions.Comment: 20 page
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