149 research outputs found
Asymptotics of first-passage percolation on 1-dimensional graphs
In this paper we consider first-passage percolation on certain 1-dimensional
periodic graphs, such as the nearest
neighbour graph for . We find that both length and weight of
minimal-weight paths present a typical 1-dimensional asymptotic behaviour.
Apart from a strong law of large numbers, we derive a central limit theorem, a
law of the iterated logarithm, and a Donsker theorem for these quantities. In
addition, we prove that the mean and variance of the length and weight of the
minimizing path between two points are monotone in the distance between the
points.
The main idea used to deduce the mentioned properties is the exposure of a
regenerative structure within the process. We describe this structure carefully
and show how it can be used to obtain a detailed description of the process
based on classical theory for i.i.d.\ sequences. In addition, we show how the
regenerative idea can be used to couple two first-passage processes to
eventually coincide. Using this coupling we derive a 0-1 law.Comment: 35 pages. The second version is drastically shortened from the first.
Some arguments have been rewritten and the introduction updated.
Content-wise, the paper remains the sam
Gilbert's disc model with geostatistical marking
We study a variant of Gilbert's disc model, in which discs are positioned at
the points of a Poisson process in with radii determined by an
underlying stationary and ergodic random field
, independent of the Poisson process. When
the random field is independent of the point process one often talks about
'geostatistical marking'. We examine how typical properties of interest in
stochastic geometry and percolation theory, such as coverage probabilities and
the existence of long-range connections, differ between Gilbert's model with
radii given by some random field and Gilbert's model with radii assigned
independently, but with the same marginal distribution. Among our main
observations we find that complete coverage of does not
necessarily happen simultaneously, and that the spatial dependence induced by
the random field may both increase as well as decrease the critical threshold
for percolation.Comment: 22 page
Existence of an unbounded vacant set for subcritical continuum percolation
We consider the Poisson Boolean percolation model in , where
the radii of each ball is independently chosen according to some probability
measure with finite second moment. For this model, we show that the two
thresholds, for the existence of an unbounded occupied and an unbounded vacant
component, coincide. This complements a recent study of the sharpness of the
phase transition in Poisson Boolean percolation by the same authors. As a
corollary it follows that for Poisson Boolean percolation in ,
for any , finite moment of order is both necessary and sufficient
for the existence of a nontrivial phase transition for the vacant set.Comment: 9 page
Inhomogeneous first-passage percolation
We study first-passage percolation where edges in the left and right
half-planes are assigned values according to different distributions. We show
that the asymptotic growth of the resulting inhomogeneous first-passage process
obeys a shape theorem, and we express the limiting shape in terms of the
limiting shapes for the homogeneous processes for the two weight distributions.
We further show that there exist pairs of distributions for which the rate of
growth in the vertical direction is strictly larger than the rate of growth of
the homogeneous process with either of the two distributions, and that this
corresponds to the creation of a defect along the vertical axis in the form of
a `pyramid'.Comment: 25 pages, 1 figur
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