29,882 research outputs found
Low linear orderings
We say that L is weakly η-like if L/⌠is isomorphic to the natural ordering of rational numbers. We construct a computable presentation of any low weakly η-like linear ordering with no strongly η-like interval. Also we prove that there exists a noncomputably presentable low2 weakly η-like linear ordering with no strongly η-like interval. © ; 2010 The Author. Published by Oxford University Press. All rights reserved
Linear Orderings of Low Degree
We consider the class of so-called k-quasidiscrete linear orderings, show that every k-quasi-discrete ordering of low degree has a computable representation, and study estimates for the complexity of all isomorphisms constructed in the article. © 2010 Pleiades Publishing, Ltd
On Locality-Sensitive Orderings and Their Applications
For any constant d and parameter epsilon > 0, we show the existence of (roughly) 1/epsilon^d orderings on the unit cube [0,1)^d, such that any two points p, q in [0,1)^d that are close together under the Euclidean metric are "close together" in one of these linear orderings in the following sense: the only points that could lie between p and q in the ordering are points with Euclidean distance at most epsilon | p - q | from p or q. These orderings are extensions of the Z-order, and they can be efficiently computed.
Functionally, the orderings can be thought of as a replacement to quadtrees and related structures (like well-separated pair decompositions). We use such orderings to obtain surprisingly simple algorithms for a number of basic problems in low-dimensional computational geometry, including (i) dynamic approximate bichromatic closest pair, (ii) dynamic spanners, (iii) dynamic approximate minimum spanning trees, (iv) static and dynamic fault-tolerant spanners, and (v) approximate nearest neighbor search
Î2 0 -copies of linear orderings
It is proved that, for any n Ï, there exist countable linear orderings Ln whose Î 2 0 -spectrum consists of exactly all non n-low Î 2 0 -degrees. Properties of such orderings are examined, for n = 1 and n = 2. © 2006 Springer Science+Business Media, Inc
Scaling of the Fano effect of the in-plane Fe-As phonon and the superconducting critical temperature in BaKFeAs
By means of infrared spectroscopy we determine the temperature-doping phase
diagram of the Fano effect for the in-plane Fe-As stretching mode in
BaKFeAs. The Fano parameter , which is a
measure of the phonon coupling to the electronic particle-hole continuum, shows
a remarkable sensitivity to the magnetic/structural orderings at low
temperatures. More strikingly, at elevated temperatures in the
paramagnetic/tetragonal state we find a linear correlation between and
the superconducting critical temperature . Based on theoretical
calculations and symmetry considerations, we identify the relevant interband
transitions that are coupled to the Fe-As mode. In particular, we show that a
sizable orbital component at the Fermi level is fundamental for the Fano
effect and possibly also for the superconducting pairing.Comment: Supplemental materials are available upon reques
Estimating an NBA player's impact on his team's chances of winning
Traditional NBA player evaluation metrics are based on scoring differential
or some pace-adjusted linear combination of box score statistics like points,
rebounds, assists, etc. These measures treat performances with the outcome of
the game still in question (e.g. tie score with five minutes left) in exactly
the same way as they treat performances with the outcome virtually decided
(e.g. when one team leads by 30 points with one minute left). Because they
ignore the context in which players perform, these measures can result in
misleading estimates of how players help their teams win. We instead use a win
probability framework for evaluating the impact NBA players have on their
teams' chances of winning. We propose a Bayesian linear regression model to
estimate an individual player's impact, after controlling for the other players
on the court. We introduce several posterior summaries to derive rank-orderings
of players within their team and across the league. This allows us to identify
highly paid players with low impact relative to their teammates, as well as
players whose high impact is not captured by existing metrics.Comment: To appear in the Journal of Quantitative Analysis of Spor
Comparing linguistic judgments and corpus frequencies as windows on grammatical competence: A study of argument linearization in German clauses
We present an overview of several corpus studies we carried out into the frequencies of argument NP orderings in the midïŹeld of subordinate and main clauses of German. Comparing the corpus frequencies with grammaticality ratings published by Kellerâs (2000), we observe a âgrammaticalityâfrequency gapâ: Quite a few argument orderings with zero corpus frequency are nevertheless assigned mediumârange grammaticality ratings. We propose an explanation in terms of a two-factor theory. First, we hypothesize that the grammatical induction component needs a sufficient number of exposures to a syntactic pattern to incorporate it into its repertoire of more or less stable rules of grammar. Moderately to highly frequent argument NP orderings are likely have attained this status, but not their zero-frequency counterparts. This is why the latter argument sequences cannot be produced by the grammatical encoder and are absent from the corpora. Secondly, we assumed that an extraneous (nonlinguistic) judgment process biases the ratings of moderately grammatical linear order patterns: Confronted with such structures, the informants produce their own âideal deliveryâ variant of the to-be-rated target sentence and evaluate the similarity between the two versions. A high similarity score yielded by this judgment then exerts a positive bias on the grammaticality ratingâa score that should not be mistaken for an authentic grammaticality rating. We conclude that, at least in the linearization domain studied here, the goal of gaining a clear view of the internal grammar of language users is best served by a combined strategy in which grammar rules are founded on structures that elicit moderate to high grammaticality ratings and attain at least moderate usage frequencies
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