21,651 research outputs found
Three implications of learning behaviour for price processes.
no abstract availableConsumers' preferences; Economics -- Psychological aspects;
Intersections on tropical moduli spaces
This article explores to which extent the algebro-geometric theory of
rational descendant Gromov-Witten invariants can be carried over to the
tropical world. Despite the fact that the tropical moduli-spaces we work with
are non-compact, the answer is surprisingly positive. We discuss the string,
divisor and dilaton equations, we prove a splitting lemma describing the
intersection with a "boundary" divisor and we prove general tropical versions
of the WDVV resp. topological recursion equations (under some assumptions). As
a direct application, we prove that the toric varieties ,
, and with Psi-conditions only
in combination with point conditions, the tropical and classical descendant
Gromov-Witten invariants coincide (which extends the result for
in Markwig-Rau-2008). Our approach uses tropical intersection theory and can
unify and simplify some parts of the existing tropical enumerative geometry
(for rational curves).Comment: 40 pages, 17 Postscript figures; updated to fit the published versio
Radio interferometric imaging of spatial structure that varies with time and frequency
The spatial-frequency coverage of a radio interferometer is increased by
combining samples acquired at different times and observing frequencies.
However, astrophysical sources often contain complicated spatial structure that
varies within the time-range of an observation, or the bandwidth of the
receiver being used, or both. Image reconstruction algorithms can been designed
to model time and frequency variability in addition to the average intensity
distribution, and provide an improvement over traditional methods that ignore
all variability. This paper describes an algorithm designed for such
structures, and evaluates it in the context of reconstructing three-dimensional
time-varying structures in the solar corona from radio interferometric
measurements between 5 GHz and 15 GHz using existing telescopes such as the
EVLA and at angular resolutions better than that allowed by traditional
multi-frequency analysis algorithms.Comment: 12 pages, 4 figures. SPIE Proceedings, Optical
Engineering+Applications; Image Reconstruction from Incomplete Dat
Existence of graphs with sub exponential transitions probability decay and applications
In this paper, we present a complete proof of the construction of graphs with
bounded valency such that the simple random walk has a return probability at
time at the origin of order for fixed and with Folner function . We begin
by giving a more detailled proof of this result contained in (see
\cite{ershdur}). In the second part, we give an application of the existence of
such graphs. We obtain bounds of the correct order for some functional of the
local time of a simple random walk on an infinite cluster on the percolation
model.Comment: 46 page
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