108,719 research outputs found
A multivalued version of the Radon-Nikodym theorem, via the single-valued Gould integral
Some topics concerning the Gould integral are presented here: new results of
integrability on finite measure spaces with values in an M-space are given,
together with a Radon-Nikodym theorem relative to a Gould-type integral of real
functions with respect to a multisubmeasure.Comment: 19 page
Bayesian model-based spatiotemporal survey design for log-Gaussian Cox process
In geostatistics, the design for data collection is central for accurate
prediction and parameter inference. One important class of geostatistical
models is log-Gaussian Cox process (LGCP) which is used extensively, for
example, in ecology. However, there are no formal analyses on optimal designs
for LGCP models. In this work, we develop a novel model-based experimental
design for LGCP modeling of spatiotemporal point process data. We propose a new
spatially balanced rejection sampling design which directs sampling to
spatiotemporal locations that are a priori expected to provide most
information. We compare the rejection sampling design to traditional balanced
and uniform random designs using the average predictive variance loss function
and the Kullback-Leibler divergence between prior and posterior for the LGCP
intensity function. Our results show that the rejection sampling method
outperforms the corresponding balanced and uniform random sampling designs for
LGCP whereas the latter work better for models with Gaussian models. We perform
a case study applying our new sampling design to plan a survey for species
distribution modeling on larval areas of two commercially important fish stocks
on Finnish coastal areas. The case study results show that rejection sampling
designs give considerable benefit compared to traditional designs. Results show
also that best performing designs may vary considerably between target species
Signed topological measures on locally compact spaces
In this paper we define and study signed deficient topological measures and
signed topological measures (which generalize signed measures) on locally
compact spaces. We prove that a signed deficient topological measure is
-smooth on open sets and -smooth on compact sets. We show that the
family of signed measures that are differences of two Radon measures is
properly contained in the family of signed topological measures, which in turn
is properly contained in the family of signed deficient topological measures.
Extending known results for compact spaces, we prove that a signed topological
measure is the difference of its positive and negative variations if at least
one variation is finite; we also show that the total variation is the sum of
the positive and negative variations. If the space is locally compact,
connected, locally connected, and has the Alexandroff one-point
compactification of genus 0, a signed topological measure of finite norm can be
represented as a difference of two topological measures.Comment: 23 page
Categorifying measure theory: a roadmap
A program for categorifying measure theory is outlined.Comment: AMS-LaTeX + xy-pic. 90 page
Supermartingale Deomposition with General Index Set
We prove results on the existence of Dol\'{e}ans-Dade measures and of the
Doob-Meyer decomposition for supermartingales indexed by a general index se
Model interpretation through lower-dimensional posterior summarization
Nonparametric regression models have recently surged in their power and
popularity, accompanying the trend of increasing dataset size and complexity.
While these models have proven their predictive ability in empirical settings,
they are often difficult to interpret and do not address the underlying
inferential goals of the analyst or decision maker. In this paper, we propose a
modular two-stage approach for creating parsimonious, interpretable summaries
of complex models which allow freedom in the choice of modeling technique and
the inferential target. In the first stage a flexible model is fit which is
believed to be as accurate as possible. In the second stage, lower-dimensional
summaries are constructed by projecting draws from the distribution onto
simpler structures. These summaries naturally come with valid Bayesian
uncertainty estimates. Further, since we use the data only once to move from
prior to posterior, these uncertainty estimates remain valid across multiple
summaries and after iteratively refining a summary. We apply our method and
demonstrate its strengths across a range of simulated and real datasets. Code
to reproduce the examples shown is avaiable at github.com/spencerwoody/ghostComment: 40 pages, 16 figure
Finitely additive measures and complementability of Lipschitz-free spaces
We prove in particular that the Lipschitz-free space over a
finitely-dimensional normed space is complemented in its bidual. For Euclidean
spaces the norm of the respective projection is . As a tool to obtain the
main result we establish several facts on the structure of finitely additive
measures on finitely-dimensional spaces.Comment: 24 pages; we corrected some misprints, reorganized a bit the
introduction and added few comments (in particular one on the Leray
projection
Absolutely Summing Operators on non commutative -algebras and applications
Let be a Banach space that does not contain any copy of and \A
be a non commutative -algebra. We prove that every absolutely summing
operator from \A into is compact, thus answering a question of Pe\l
czynski.
As application, we show that if is a compact metrizable abelian group and
is a Riesz subset of its dual then every countably additive
\A^*-valued measure with bounded variation and whose Fourier transform is
supported by has relatively compact range. Extensions of the same
result to symmetric spaces of measurable operators are also presented
On reproducing kernels, and analysis of measures
Starting with the correspondence between positive definite kernels on the one
hand and reproducing kernel Hilbert spaces (RKHSs) on the other, we turn to a
detailed analysis of associated measures and Gaussian processes. Point of
departure: Every positive definite kernel is also the covariance kernel of a
Gaussian process.
Given a fixed sigma-finite measure , we consider positive definite
kernels defined on the subset of the sigma algebra having finite measure.
We show that then the corresponding Hilbert factorizations consist of signed
measures, finitely additive, but not automatically sigma-additive. We give a
necessary and sufficient condition for when the measures in the RKHS, and the
Hilbert factorizations, are sigma-additive. Our emphasis is the case when
is assumed non-atomic. By contrast, when is known to be atomic, our
setting is shown to generalize that of Shannon-interpolation. Our RKHS-approach
further leads to new insight into the associated Gaussian processes, their
It\^{o} calculus and diffusion. Examples include fractional Brownian motion,
and time-change processes
On subadditive functions upper bounded on a 'large' set
The notion of a shift-compact set in an abelian topological group plays a
significant role in functional equations and inequalities, especially so since
each Borel set that is not Haar-meagre, alternatively not Haar-null, is
necessarily shift-compact for completely metrizable (see \cite{BJ} and
\cite{BinO8}). Although in general boundedness of a subadditive function does
not imply its continuity, here we prove that each subadditive function
(i.e. with the function satisfying for ) bounded above on a~shift-compact (non-Haar-null,
non-Haar-meagre) set is locally bounded at each point of the domain. Our
results refer to \cite[Chapter~XVI]{Kuczma} and papers by N.H.~Bingham and
A.J.~Ostaszewski \cite{BO,BinO1,BinO2,BinO6,BinO7}
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