1,230 research outputs found
Limit Laws for Functions of Fringe trees for Binary Search Trees and Recursive Trees
We prove limit theorems for sums of functions of subtrees of binary search
trees and random recursive trees. In particular, we give simple new proofs of
the fact that the number of fringe trees of size in the binary search
tree and the random recursive tree (of total size ) asymptotically has a
Poisson distribution if , and that the distribution is
asymptotically normal for . Furthermore, we prove similar
results for the number of subtrees of size with some required property , for example the number of copies of a certain fixed subtree . Using
the Cram\'er-Wold device, we show also that these random numbers for different
fixed subtrees converge jointly to a multivariate normal distribution. As an
application of the general results, we obtain a normal limit law for the number
of -protected nodes in a binary search tree or random recursive tree.
The proofs use a new version of a representation by Devroye, and Stein's
method (for both normal and Poisson approximation) together with certain
couplings
Investigating interaction-induced chaos using time-dependent density functional theory
Systems whose underlying classical dynamics are chaotic exhibit signatures of
the chaos in their quantum mechanics. We investigate the possibility of using
time-dependent density functional theory (TDDFT) to study the case when chaos
is induced by electron-interaction alone. Nearest-neighbour level-spacing
statistics are in principle exactly and directly accessible from TDDFT. We
discuss how the TDDFT linear response procedure can reveal the mechanism of
chaos induced by electron-interaction alone. A simple model of a two-electron
quantum dot highlights the necessity to go beyond the adiabatic approximation
in TDDFT.Comment: 8 pages, 4 figure
Two population models with constrained migrations
We study two models of population with migration. We assume that we are given
infinitely many islands with the same number r of resources, each individual
consuming one unit of resources. On an island lives an individual whose
genealogy is given by a critical Galton-Watson tree. If all the resources are
consumed, any newborn child has to migrate to find new resources. In this
sense, the migrations are constrained, not random. We will consider first a
model where resources do not regrow, so the r first born individuals remain on
their home island, whereas their children migrate. In the second model, we
assume that resources regrow, so only r people can live on an island at the
same time, the supernumerary ones being forced to migrate. In both cases, we
are interested in how the population spreads on the islands, when the number of
initial individuals and available resources tend to infinity. This mainly
relies on computing asymptotics for critical random walks and functionals of
the Brownian motion.Comment: 38 pages, 12 figure
On the asymptotic behavior of some Algorithms
A simple approach is presented to study the asymptotic behavior of some
algorithms with an underlying tree structure. It is shown that some asymptotic
oscillating behaviors can be precisely analyzed without resorting to complex
analysis techniques as it is usually done in this context. A new explicit
representation of periodic functions involved is obtained at the same time.Comment: November 200
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