Results 21 to 30 of about 4,784,645 (352)
Roots of Polynomials and Umbilics of Surfaces [PDF]
Results in Math. 78 (2023) 229, 2022 For certain polynomials we relate the number of roots inside the unit circle with the index of a non-degenerate isolated umbilic point on a real analytic surface in Euclidean 3-space. In particular, for $N>0$ we prove that for a certain ($N+2$)-real dimensional family of complex polynomials of degree $N$, the number of roots inside the unit circle is
arxiv +1 more source
Decisions on Seasonal Unit Roots [PDF]
Journal of Statistical Computation and Simulation, 2000 Decisions on the presence of seasonal unit roots in economic time series are commonly taken on the basis of statistical hypothesis tests. Some of these tests have absence of unit roots as the null hypothesis, while others use unit roots as their null.
Kunst, Robert M., Reutter, Michael
openaire +5 more sources
Unit Roots and Cointegration [PDF]
, 2019 In this chapter we investigate how the possible presence of unit roots and cointegration affects forecasting with big data. As most macroeoconomic time series are very persistent and may contain unit roots, a proper handling of unit roots and cointegration is of paramount importance for macroeconomic forecasting. The high-dimensional nature of big data
Stephan Smeekes, Etienne Wijler
openaire +4 more sources
Can Obstetric Risk Factors Predict Fetal Acidaemia at Birth? A Retrospective Case-Control Study
Journal of Pregnancy, 2018 Background. Despite major advances in perinatal medicine, intrapartum asphyxia remains a leading and potentially preventable cause of perinatal mortality and long-term morbidity. The umbilical cord pH is considered an essential criteria for the diagnosis
Habiba Kapaya +3 more
doaj +1 more source
Review on Efficiency and Anomalies in Stock Markets
Economies, 2020 The efficient-market hypothesis (EMH) is one of the most important economic and financial hypotheses that have been tested over the past century. Due to many abnormal phenomena and conflicting evidence, otherwise known as anomalies against EMH, some ...
Kai-Yin Woo +3 more
doaj +1 more source
p-adic variation of unit root L-functions [PDF]
Pacific J. Math. 288 (2017) 129-156, 2015 Dwork's conjecture, now proven by Wan, states that unit root L-functions "coming from geometry" are p-adic meromorphic. In this paper we study the p-adic variation of a family of unit root L-functions coming from a suitable family of toric exponential sums. In this setting, we find that the unit root L-functions each have a unique p-adic unit root.
arxiv +1 more source
UNIT ROOTS IN PERIODIC AUTOREGRESSIONS [PDF]
Journal of Time Series Analysis, 1996 Abstract. This paper analyzes the presence and consequences of a unit root in periodic autoregressive models for univariate quarterly time series. First, we consider various representations of such models, including a new parametrization which facilitates imposing a unit root restriction.
Boswijk, H.P., Franses, P.H.
openaire +4 more sources
Testing for a Unit Root in Time Series Regression
, 1988 This Paper Proposes Some New Tests for Detecting the Presence of a Unit Root in Quite General Time Series Modesl. Our Approach Is Nonparametric with Respect to Nuisance Parameters and Thereby Allows for a Very Wide Class of Weakly Dependent and Possibly ...
P. Phillips
semanticscholar +1 more source
An Assessment of Purchasing Power Parity in the Long-Run: Evidence from India and its four Major Trading Partners [PDF]
Eurasian Journal of Business and EconomicsThe present study focuses on evaluating the validity of the Relative Purchasing Power Parity (RPPP) theory for India and its four major trading partner nations namely the United States, China, the United Arab Emirates, and Saudi Arabia using monthly time
Manjinder KAUR, Navpreet KULAAR
doaj +1 more source
A Simple Panel Unit Root Test in the Presence of Cross Section Dependence
, 2003 A number of panel unit root tests that allow for cross section dependence have been proposed in the literature, notably by Bai and Ng (2002), Moon and Perron (2003) and Phillips and Sul (2002) who use orthogonalization type procedures to asymptotically ...
M. Pesaran
semanticscholar +1 more source