Results 101 to 110 of about 12,262 (250)

An inequality for Hilbert series of graded algebras.

MATHEMATICA SCANDINAVICA, 1985
Let \(R=k[X_ 1,...,X_ n]/I\), where k is a field and \(I=(f_ 1,...,f_ r)\) is a homogeneous ideal. Let \(d=\dim R\), \(g=depth R\) and \(d_ i=\deg f_ i\). We define \(Hilb_ R(Z)=\sum (\dim_ kR_ i)z^ i,\) where \(R=\oplus R_ i\) is the natural decomposition of R into graded pieces. - Theorem.
openaire   +3 more sources

Band‐Pass Filtering With High‐Dimensional Time Series. A Synthetic Indicator of the Medium‐to‐Long Run Component of Growth

Journal of Time Series Analysis, EarlyView.
ABSTRACT The paper deals with the construction of a synthetic indicator of economic growth, obtained by projecting a quarterly measure of aggregate economic activity, namely gross domestic product (GDP), into the space spanned by a finite number of smooth principal components, representative of the medium‐to‐long‐run component of economic growth of a ...
Alessandro Giovannelli, Marco Lippi, Tommaso Proietti   +2 more
wiley   +1 more source

Spectral Analysis of Time Series of Permanent GPS Station Positions Using HHT [PDF]

فصلنامه علوم و فناوری فضایی, 2011
In this paper, Hilbert Huang transform (HHT) for time series analysis of the status of permanent GPS stations can be provided. Hilbert Huang transform and its, related spectrun is a new method for the analysis of nonlinear processes.This method ...
F. Nobakht-Orsi, M. A. Sharifi, A. R. Safari   +2 more
doaj  

On Hilbert's Inequality for Double Series and Its Applications

International Journal of Mathematics and Mathematical Sciences, 2008
This study shows that a refinement of the Hilbert inequality for double series can be established by introducing a real function u(x) and a parameter λ.
Zhou Yu, Gao Mingzhe
doaj   +1 more source

Testing Distributional Granger Causality With Entropic Optimal Transport

Journal of Time Series Analysis, EarlyView.
ABSTRACT We develop a novel nonparametric test for Granger causality in distribution based on entropic optimal transport. Unlike classical mean‐based approaches, the proposed method directly compares the full conditional distributions of a response variable with and without the history of a candidate predictor.
Tao Wang
wiley   +1 more source

Some New Hilbert's Type Inequalities

Journal of Inequalities and Applications, 2009
Some new inequalities similar to Hilbert's type inequality involving series of nonnegative terms are established.
Chang-Jian Zhao, Wing-Sum Cheung
doaj   +1 more source

Sparse Causal Dynamic Linear Regression

Journal of Time Series Analysis, EarlyView.
ABSTRACT We develop a sparse causal dynamic regression framework for long multivariate time series. With very long time series, the potentially large number of lags and leads in a dynamic regression model often makes time‐domain estimation numerically unstable or intractable.
Rui Huang, Kung‐Sik Chan
wiley   +1 more source

Optimal Portfolio Choice With Cross‐Impact Propagators

Mathematical Finance, EarlyView.
ABSTRACT We consider a class of optimal portfolio choice problems in continuous time where the agent's transactions create both transient cross‐impact driven by a matrix‐valued Volterra propagator, as well as temporary price impact. We formulate this problem as the maximization of a revenue‐risk functional, where the agent also exploits available ...
Eduardo Abi Jaber, Eyal Neuman, Sturmius Tuschmann   +2 more
wiley   +1 more source

Hilbert Series of a Quotient Algebra of Polynomials

Journal of Algebra, 1995
Let \(R = k[x_1, \dots, x_r]/(F_1, \dots, F_n)\), where \(F_i\) are homogeneous of degree \(d_i = \deg F_i\) (and \(\deg x_i = 1\) for all \(i)\). Then \(R\) is graded, \(R = \bigoplus R_i\), and the Hilbert series of \(R\) is \(\text{Hilb} R(t) = \sum \dim_k R_i t^i\). It has been conjectured that \(\text{Hilb} R(t) \geq |(1 - t)^r \prod^n_{k = 1} (1 -
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Phainesthai Formalised? Cogito, ergo ‘res’ sum in Conscious Agent Theory

Metaphilosophy, EarlyView.
Abstract The problem of consciousness remains the most intractable question in the philosophy of mind. Scientific approaches to consciousness, in their effort to provide a systematic account, impose determinate structures. This methodological necessity encounters a dilemma: it seeks to define what is never self‐identical. This paper considers Conscious
Killian McGrath
wiley   +1 more source