Articles
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07/19/2016--
05/31/2016
Dynamic index and LZ factorization in compressed space
In this paper, we propose a new \emph{dynamic compressed index} of $O(w)$
space for a dynamic text $T$, where $w = O(\min(z \log N \log^*M, N))$ is the
size of the signature encoding of $T$, $z$ is the size of the Lempel-Ziv77
(LZ77) factorization of $T$, $N$ is the length of $T$, and $M \geq 3N$ is an
integer that can be handled in constant time under word RAM model. Our index
supports searching for a pattern $P$ in $T$ in $O(|P| f_{\mathcal{A}} + \log w
\log |P| \log^* M (\log N + \log |P| \log^* M) + \mathit{occ} \log N)$ time and
insertion/deletion of a substring of length $y$ in $O((y+ \log N\log^* M)\log w
\log N \log^* M)$ time, where $f_{\mathcal{A}} = O(\min \{ \frac{\log\log M
\log\log w}{\log\log\log M}, \sqrt{\frac{\log w}{\log\log w}} \})$. Also, we
propose a new space-efficient LZ77 factorization algorithm for a given text of
length $N$, which runs in $O(N f_{\mathcal{A}} + z \log w \log^3 N (\log^*
N)^2)$ time with $O(w)$ working space.
Takaaki Nishimoto
Tomohiro I
Shunsuke Inenaga
Hideo Bannai
Masayuki Takeda
05/01/2013--
10/23/2012
New algorithms for binary jumbled pattern matching
Given a pattern $P$ and a text $T$, both strings over a binary alphabet, the
binary jumbled string matching problem consists in telling whether any
permutation of $P$ occurs in $T$. The indexed version of this problem, i.e.,
preprocessing a string to efficiently answer such permutation queries, is hard
and has been studied in the last few years. Currently the best bounds for this
problem are $O(n^2/\log^2 n)$ (with O(n) space and O(1) query time) and
$O(r^2\log r)$ (with O(|L|) space and $O(\log|L|)$ query time), where $r$ is
the length of the run-length encoding of $T$ and $|L| = O(n)$ is the size of
the index. In this paper we present new results for this problem. Our first
result is an alternative construction of the index by Badkobeh et al. that
obtains a trade-off between the space and the time complexity. It has
$O(r^2\log k + n/k)$ complexity to build the index, $O(\log k)$ query time, and
uses $O(n/k + |L|)$ space, where $k$ is a parameter. The second result is an
$O(n^2 \log^2 w / w)$ algorithm (with O(n) space and O(1) query time), based on
word-level parallelism where $w$ is the word size in bits.
Emanuele Giaquinta
Szymon Grabowski
09/18/2010--
09/18/2010
Priority Range Trees
We describe a data structure, called a priority range tree, which
accommodates fast orthogonal range reporting queries on prioritized points. Let
$S$ be a set of $n$ points in the plane, where each point $p$ in $S$ is
assigned a weight $w(p)$ that is polynomial in $n$, and define the rank of $p$
to be $r(p)=\lfloor \log w(p) \rfloor$. Then the priority range tree can be
used to report all points in a three- or four-sided query range $R$ with rank
at least $\lfloor \log w \rfloor$ in time $O(\log W/w + k)$, and report $k$
highest-rank points in $R$ in time $O(\log\log n + \log W/w' + k)$, where
$W=\sum_{p\in S}{w(p)}$, $w'$ is the smallest weight of any point reported, and
$k$ is the output size. All times assume the standard RAM model of computation.
If the query range of interest is three sided, then the priority range tree
occupies $O(n)$ space, otherwise $O(n\log n)$ space is used to answer
four-sided queries. These queries are motivated by the Weber--Fechner Law,
which states that humans perceive and interpret data on a logarithmic scale.
Michael T. Goodrich
Darren Strash
09/13/2019--
09/06/2019
Minimal Unique Substrings and Minimal Absent Words in a Sliding Window
A substring $u$ of a string $T$ is called a minimal unique substring (MUS) of
$T$ if $u$ occurs exactly once in $T$ and any proper substring of $u$ occurs at
least twice in $T$. A string $w$ is called a minimal absent word (MAW) of $T$
if $w$ does not occur in $T$ and any proper substring of $w$ occurs in $T$. In
this paper, we study the problems of computing MUSs and MAWs in a sliding
window over a given string $T$. We first show how the set of MUSs can change in
a sliding window over $T$, and present an $O(n\log\sigma)$-time and
$O(d)$-space algorithm to compute MUSs in a sliding window of width $d$ over
$T$, where $\sigma$ is the maximum number of distinct characters in every
window. We then give tight upper and lower bounds on the maximum number of
changes in the set of MAWs in a sliding window over $T$. Our bounds improve on
the previous results in [Crochemore et al., 2017].
Takuya Mieno
Yuki Kuhara
Tooru Akagi
Yuta Fujishige
Yuto Nakashima
Shunsuke Inenaga
Hideo Bannai
Masayuki Takeda
06/15/2024--
06/15/2024
Ancient solutions to the Allen Cahn equation in catenoids
Let $N\geq 2$ and $F:\mathbb{R}^N\to \mathbb{R} $ be the unique increasing
radially symmetric function satisfying the minimal surface equation for graphs
with the initial conditions $F(1)=0$ and $\lim_{r\to 1}F_r(r)=\infty;$ $r=|x|.$
We construct an ancient solution to Allen-Cahn equation $\tilde u_t =
\Delta_{M} \tilde u + (1-{\tilde u}^2)\tilde u$ in $M\times(-\infty,0),$ where
$M=\{(x, \pm F(|x|)):\;x\in\mathbb{R}^N,\;|x|\geq1\}$ is a $N$-dimensional
catenoid in $\mathbb{R}^{N+1}$ and $\Delta_{M}$ is the Laplace Beltrami
operator of $M.$ In particular, we construct a solution of the form
$u(t,r,F(r))=u(t,r,-F(r))$ such that
$$ u(t,r,F(r)) \approx \sum_{j=1}^k (-1)^{j-1}w(r-\rho_j(t)) - \frac 12 (1+
(-1)^{k}) \quad \hbox{ as } t\to -\infty, $$ where $w(s)$ is a solution of $w''
+ (1-w^2)w=0$ with $w(\pm \infty)= \pm 1,$ given by $w(s) = \tanh \left(\frac
s{\sqrt{2}} \right),$ and
$$\rho_j(t)=\sqrt{-2(n-1)t}+\frac{1}{\sqrt{2}}\left(j-\frac{k+1}{2}\right)\log\left(\frac
{|t|}{\log |t| }\right)+ O(1),\quad j=1,\ldots ,k.$$
Konstantinos T. Gkikas
02/18/2009--
02/18/2009
Threshold corrections to the gamma t anti-t vertex at O(alpha alpha(s))
In these proceedings a recent calculation of the last missing piece of the
two-loop O(alpha alpha(s)) corrections to gamma t anti-t vertex at the t anti-t
threshold due to the exchange of a W boson and a gluon is summarised. The
calculation constitutes a building block of the top quark threshold production
cross section at electron positron colliders.
Dirk Seidel
09/06/2021--
12/30/2018
Meromorphic solutions of delay differential equations related to logistic type and generalizations
Let $\{b_{j}\}_{j=1}^{k}$ be meromorphic functions, and let $w$ be admissible
meromorphic solutions of delay differential equation
$$w'(z)=w(z)\left[\frac{P(z,
w(z))}{Q(z,w(z))}+\sum_{j=1}^{k}b_{j}(z)w(z-c_{j})\right]$$ with distinct
delays $c_{1}, \ldots, c_{k}\in\mathbb{C}\setminus\{0\},$ where the two nonzero
polynomials $P(z, w(z))$ and $Q(z, w(z))$ in $w$ with meromorphic coefficients
are prime each other. We obtain that if $\limsup_{r\rightarrow\infty}\frac{\log
T(r, w)}{r}=0,$ then $$deg_{w}(P/Q)\leq k+2.$$ Furthermore, if $Q(z, w(z))$ has
at least one nonzero root, then $deg_{w}(P)=deg_{w}(Q)+1\leq k+2;$ if all roots
of $Q(z, w(z))$ are nonzero, then $deg_{w}(P)=deg_{w}(Q)+1\leq k+1;$ if
$deg_{w}(Q)=0,$ then $deg_{w}(P)\leq 1.$\par
In particular, whenever $deg_{w}(Q)=0$ and $deg_{w}(P)\leq 1$ and without the
growth condition, any admissible meromorphic solution of the above delay
differential equation (called Lenhart-Travis' type logistic delay differential
equation) with reduced form can not be an entire function $w$ satisfying
$\overline{N}(r, \frac{1}{w})=O(N(r, \frac{1}{w}));$ while if all coefficients
are rational functions, then the condition $\overline{N}(r, \frac{1}{w})=O(N(r,
\frac{1}{w}))$ can be omitted. Furthermore, any admissible meromorphic solution
of the logistic delay differential equation (that is, for the simplest special
case where $k=1$ and $deg_{w}(P/Q)=0$ ) satisfies that $N(r,w)$ and $T(r, w)$
have the same growth category. Some examples support our results.
Ling Xu
Tingbin Cao
07/27/2006--
01/20/2006
Half-Life of $^{14}$O
We have measured the half-life of $^{14}$O, a superallowed $(0^{+} \to
0^{+})$ $\beta$ decay isotope. The $^{14}$O was produced by the
$^{12}$C($^{3}$He,n)$^{14}$O reaction using a carbon aerogel target. A
low-energy ion beam of $^{14}$O was mass separated and implanted in a thin
beryllium foil. The beta particles were counted with plastic scintillator
detectors. We find $t_{1/2} = 70.696\pm 0.052$ s. This result is $1.5\sigma$
higher than an average value from six earlier experiments, but agrees more
closely with the most recent previous measurement.
J. T. Burke
P. A. Vetter
S. J. Freedman
B. K. Fujikawa
W. T. Winter
06/24/2009--
11/07/2005
Density of paths of iterated Levy transforms of Brownian motion
The Levy transform of a Brownian motion B is the Brownian motion B't, the
integral over (O,t) of sign of Bs with respect to dBs. Call T the corresponding
transformation on the Wiener space W. We establish that a.s. the orbit of w in
W under T is dense in W for the compact uniform convergence topology.
Marc Malric
02/20/2018--
12/11/2017
A review about w{ü}stite Fe 1-z O, pseudo-phases and defect clustering
Thermodynamic properties and structural aspects of the non-stoichiometric
w\"ustite Fe 1-z O, and its modifications-the so-called pseudo-phases-as
functions of composition z and equilibrium temperature are reviewed from 1960
to present (159 references). The focus is first put on the complexity of the
equilibrium phase diagram. The first order transition W $\rightleftharpoons$ W'
is specified on the boundary iron/ w\"ustite close to 1185 K. Transitions
correlated to the modifications Wi at T(W) > 1185 K and W'j at 1185K < T(W') <
T(W) (i and j =1,2,3) are reexamined. Structural determinations based on point
defects and their clustering are recalled. A series of equilibria are
developed, trying to justify the stabilization of the pseudo-phases, which can
be interpreted in terms of transformation of defect clusters, or their mode of
distribution (percolation, superstructure) including changes in electronic
charge carriers.
Jean-Raymond Gavarri
Claude Carel
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