Let $G$ be a connected reductive algebraic group over a non-Archimedean local
field $K$, and let $\mathfrak g$ be its Lie algebra. By a theorem of
Harish-Chandra, if $K$ has characteristic zero, the Fourier transforms of
nilpotent orbital integrals are represented on the set of regular elements in
${\mathfrak g}(K)$ by locally constant functions, which, extended by zero to
all of ${\mathfrak g}(K)$, are locally integrable. In this paper, we prove that
if the group $G$ is unramified, these functions are in fact specializations of
constructible motivic exponential functions.
This paper is concerned with the values of Harish-Chandra characters of a
class of positive-depth, toral, very supercuspidal representations of $p$-adic
symplectic and special orthogonal groups, near the identity element. We declare
two representations equivalent if their characters coincide on a specific
neighbourhood of the identity (which is larger than the neighbourhood on which
Harish-Chandra local character expansion holds).
We give the p-adic and F_q((t)) analogue of the real van der Corput Lemma,
where the real condition of sufficient smoothness for the phase is replaced by
the condition that the phase is a convergent power series. This van der Corput
style result allows us, in analogy to the real situation, to study singular
Fourier transforms on suitably curved (analytic) manifolds and opens the way
for further applications.
We study Lebesgue integration of sums of products of globally subanalytic
functions and their logarithms, called constructible functions. Our first
theorem states that the class of constructible functions is stable under
integration. The second theorem treats integrability conditions in Fubini-type
settings, and the third result gives decay rates at infinity for constructible
functions. Further, we give preparation results for constructible functions
related to integrability conditions.
We present a unifying theory of fields with certain classes of analytic
functions, called fields with analytic structure. Both real closed fields and
Henselian valued fields are considered.