Narrow Results

In this paper, we present a simple toy model for a possible Ricci–Gauss–Bonnet gravity universe in which a novel form of cyclic evolution occurs where the Hubble parameter remains positive and oscillates. In this model, we have used the form for $f(R,\mathcal{𝒢})$ gravity as $\alpha R+\beta {\mathcal{𝒢}}^2$. In order to simulate cosmic transit, we have considered a time-dependent deceleration parameter oscillating in between the two phases of deceleration and acceleration which leads to a specific form for the Hubble parameter. The current periodic model predicts the deceleration–acceleration cosmic transit to happen at approximately $8.7\text{Gyr}$. The evolution of different parameters with the redshift has been plotted and analyzed. The contributions of the entropy-corrected holographic dark energy and the modified holographic Ricci dark energy density to the total energy parameter have been investigated.

In this paper, we explore the isomorphism between vector time and causality to characterize consistency of a set of checkpoints in a distributed computing. A necessary and sufficient condition, to determine if a set of local checkpoints can form a consistent global checkpoint, is presented and proved using the isomorphic power of vector time and causality. To the best of our knowledge, this is the first attempt to use the isomorphism for this purpose. This condition leads to a simple and straightforward algorithm for a guaranteed mutually consistent global checkpointing. In our approach, a process can take a checkpoint whenever and wherever it wants while other related process may be asked to take an additional checkpoint for ensuring the mutual consistency. We also show how this condition and the resulting algorithm can be used to obtain a maximum and minimum global checkpoints, another important paradigm for distributed applications.

The prototypes of mutually independent systems are systems which are localized in spacelike separated regions. In the framework of locally covariant quantum field theory, we show that the commutativity of observables in spacelike separated regions can be encoded in the tensorial structure of the functor which associates unital C*-algebras (the local observable algebras) to globally hyperbolic spacetimes. This holds under the assumption that the local algebras satisfy the split property and involves the minimal tensor product of C*-algebras.

A strictly ordered hierarchy of eight causal properties encountered in General Relativity is reviewed for the explicit case of the gravitational plane waves. Illustrative proofs are given to the effect that the place of these space-times is precisely known in the hierarchy: they are causally continuous, but not causally simple. The other conditions of the hierarchy are also discussed separately, as are some causality conditions that belong outside the hierarchy. The investigation relies on the following tools: (1) the symplectic structure appearing in certain matrix differential equations of the Riccati type; and (2) the global properties that can be derived from the isometry group generated by the Killing vector fields of the metric. Connections to some of the techniques of singularity theory are also pointed out.

Here we address the challenge of profiling causal properties and tracking the transformation of chemical compounds from an algorithmic perspective. We explore the potential of applying a computational interventional calculus based on the principles of algorithmic probability to chemical structure networks. We profile the sensitivity of the elements and covalent bonds in a chemical structure network algorithmically, asking whether reprogrammability affords information about thermodynamic and chemical processes involved in the transformation of different compound classes. We arrive at numerical results suggesting a correspondence between some physical, structural and functional properties. Our methods are capable of separating chemical classes that reflect functional and natural differences without considering any information about atomic and molecular properties. We conclude that these methods, with their links to chemoinformatics via algorithmic, probability hold promise for future research.

Intervention to support export initiatives is commonplace in both industralized and developing countries. Such intervention is underpinned by the view that exporting is good for growth, typified by the success of the South East Asian tiger economies. Yet, while the evidence is largely macroeconomic, most intervention is microeconomic, targeted at specific firms or industries. Recently a new literature has developed that is microeconomic and microeconometric, exploring determinants of entry into and survival in export markets. Key within this literature is the relationship between firm productivity and exports. This paper reviews the theoretical and empirical contributions to this literature and evaluates its contribution to our understanding of the factors driving export decisions and the consequences of export market entry from both. In addition to assessing the importance of new insights being generated, this paper speculates on new directions in which the research agenda will evolve.

This paper examines the long-term as well as short-term equilibrium relationships between the major stock indices and selected macroeconomic variables (such as money supply and interest rate) of Singapore and the United States by employing the advanced time series analysis techniques that include cointegration, Johansen multivariate cointegrated system, fractional cointegration and Granger causality. The cointegration results based on data covering the period January 1982 to December 2002 suggest that Singapore's stock prices generally display a long-run equilibrium relationship with interest rate and money supply (M1) but a similar relationship does not hold for the United States. To capture the short-run dynamics of the relationship, we replicate the same experiments with different subsets of data representing shorter time periods. It is evident that stock markets in Singapore moved in tandem with interest rate and money supply before the Asian Crisis of 1997, but this pattern was not observed after the crisis. In the United States, stock prices were strongly cointegrated with macroeconomic variables before the 1987 equity crisis but the relationships gradually weakened and totally disappeared with the emergence of Asian Crisis that also indirectly affected the United States. The results of fractional cointegration and the Johansen multivariate system are consistent with the earlier cointegration results that both Singapore and US stock markets did possess equilibrium relationships with M1 and interest rate at the early days. However, the stability of the systems was disturbed by a series of well-known financial turbulence in the past two decades and eventually weakened for Singapore and completely disappeared for the US. This may imply that monetary authority may take action to respond to the asset price turbulence in order to maintain the stability of monetary economy and thus break the existing equilibrium between stock markets and macroeconomic variables like interest rate and M1. Another possible explanation is that the market became more efficient after 1997 Asian crisis. Finally, the results of Granger causality tests uncover some systematic causal relationships, implying that stock market performance might be a good gauge for Central Bank's monetary policy adjustment.

This study investigates the determinants of savings behavior in India and the direction of causality between savings and income per capita as these have important implications for development policy. We estimate long-run savings functions for India using modern co-integration procedures. Our empirical results show that higher income per capita and improved access to banking facilities significantly improves savings in India. On the other hand, foreign savings and public savings have negative impact on private and household savings. We also carry out an analysis of the direction of causality between savings and income. The results suggest that there is a one-way causation from income per capita to the savings rate.

In a small open economy, the retail sector adds value with a lag to existing production and uses existing domestic production as an input. Therefore, demand side dynamics depend on the wholesale prices of the domestic goods, the prices of the imported goods, the nominal exchange rate, the level of indirect taxes, the marginal cost of retail production and interest rates. Hence, this mechanism provides a theoretical basis for causality from wholesale prices to consumer prices. Being motivated by this causal transmission mechanism, this paper tries to examine the causal relationship between wholesale prices and consumer prices in a small developing economy like Pakistan. Empirical methodology uses recently developed tests for the existence of a long-run relationship between wholesale prices and consumer prices. Typically, in applied analysis, testing for the existence of cointegration and causality can only be carried out once the time series properties of the data have been established. For example, tests for cointegration require the variables to be integrated to the same order, typically I(1), prior to estimation. By eliminating the need for unit root pre-testing, the tests applied here considerably simplify the inference procedure. They also reduce the potential for distortions in the inference due to the unknown properties of the testing sequence. Our findings include robust evidence that, for Pakistan, there is a bidirectional causality between wholesale prices and consumer prices. Feedback impact shows that influences from the wholesale price index (WPI) to the consumers' price index (CPI) is stronger or dominating as compared to feedback from CPI to WPI supporting the Cushing-McGarvey (1990) hypothesis.

Empirical evidence linking exports and productivity growth has been mixed and inconclusive. This study re-examines the direction of the causality between them for Malaysian industries by using the error-correction mechanism and Granger causality models. In a panel of 63 manufacturing industries, for the period of 1981 to 1999, it is found that these industries support the export-led growth and the growth-driven export hypotheses. A further look into the results indicates that there are possibilities of indirect causalities between productivity growth and export through size and capital intensity, as both exports and labor productivity have bidirectional causality with size and capital intensity.

This paper attempts to establish whether there exists any direct macroeconomic linkages between some East Asian (EA) countries on the one hand and the US on the other hand, based upon quarterly real gross domestic product (GDP) series spanning from the early 1990s. Cointegration, Granger causal relations and contemporaneous correlations of output shocks are explored. Contrary to a priori expectations, the empirical evidence suggests no direct linkages of these economies to the US, with the exception of the Malaysian economy. In the case of Malaysia, only a Granger causal relation from the US is found. All this would allude to the ability of these EA economies save one to grow independently of the US, barring a global economic crisis such as the recent one triggered off by sub-prime loans.

This study reexamines the relationship between energy consumption per capita and real GDP per capita for Indonesia, Malaysia, the Philippines, Singapore and Thailand using both panel data causality which is taking into account cross-sectional dependence and heterogeneity among the countries and time series causality tests for the period 1971–2009. The findings indicate that taking into account cross-sectional dependence has a substantial effect on the achieved results. The conservation hypothesis is supported for Indonesia, Malaysia and the Philippines. Although a bidirectional relation is found in the case of Thailand, since there is no positive effect of energy consumption on GDP, the conservation hypothesis is supported. In the pattern of Singapore, the neutrality hypothesis is supported. In addition, the increase in investment and labor force lead to more energy consumption in Indonesia, Malaysia and Thailand.

The untested assumption of linear relationship between stocks and bonds in previous empirical studies may lead to an invalid conclusion if the actual relationship is non-linear. The emphasis of this paper is on the effect of non-linearities on causal relationships between stocks and bonds in the cases of Malaysia and Singapore. Results from linearity tests indicate the existence of non-linearities in the dynamic relationship between stocks and bonds. Non-linear causality test results based on Taylor expansion suggest that non-linear causality flows from stocks to bonds and vice versa. The test further confirms that bonds with different maturity dates have different relationships with stocks.

This paper aims to ascertain whether direct macroeconomic linkages exist between some East Asian (EA) countries on the one hand and the United States (US) and Europe on the other, based upon quarterly real gross domestic product (GDP) series spanning from the early 1990s. Long-run and short-run lead-lag relations are explored within a trivariate modeling framework. Contrary to popular belief, the empirical evidence suggests generally either very nominal or no direct links at all between these EA countries and the US in terms of GDP. Direct links with Europe are completely ruled out. All these would allude to a very limited susceptibility of these EA economies to shocks in the US and Europe, barring a global economic crisis of catastrophic proportions. The growing belief that if China sneezes, the world catches the flu is also not borne out by the empirical results.

The ASEAN countries have been experiencing drastic declines in fertility of more than 10 percent, particularly since the 1990s. Though the literature on fertility has clearly delineated the importance of income, female labor force participation and infant mortality as key determinants of fertility rates (FRs), the empirical findings from previous studies remains at best mixed. This study therefore identifies the determinants of female fertility for the countries, namely Indonesia, Malaysia, Philippines, Singapore and Thailand (ASEAN-5 countries), spanning the period 1980–2010. Using the Autoregressive Distributed Lag (ARDL) cointegration and causality techniques, the main findings of the study are summarized as follows: First, a long-run (LR) stable relationship is evident between female fertility, female labor force participation, income and infant mortality for ASEAN-5. Second, there is a deviation of FRs from the short-run (SR) to the LR equilibrium for ASEAN-5, with the highest and lowest speed of adjustment recorded for Malaysia and Thailand, respectively. Third, FR and economic stability are found to be complementary in the LR for ASEAN-5. When the joint LR and SR causalities are considered, we found that female labor force participation, income and infant mortality have dynamic relationships with FR for all the five ASEAN countries.

In this study, we examine the asymmetric effects of terrorism and economic growth in Pakistan over the period 1970–2016, while considering the role of capital per worker and structural breaks. We use the non-linear ARDL approach to establish the long-run association and to estimate the short-run and long-run effects accordingly. The results indicate the presence of asymmetries in both long and short run. Moreover, 1% decrease in terrorism results in an increase of per capita income by 0.02% in the long run and 0.001% in the short run. Assuming symmetry, the long run capital share is 0.47. In asymmetric relation, a 1% increase in capital share increases output by 0.55%, whereas a 1% decrease in capital stock decreases output by 0.26%. The break effects show that the years 1993 and 2004 have negative effects on growth. The vector error correction model-based causality results indicate a unidirectional causality from terrorism to per capita income. Overall, the results highlight that terrorism is growth retarding.

This study investigates the connectedness between Bitcoin prices and major stock indices in the Asia-Pacific region from February 2012 to August 2019. Based on the wavelet transform framework, we find evidence of significant unidirectional association from Bitcoin to the selected markets in the short, medium, and long-run in the Asia-Pacific region. Overall, Asia-Pacific equity markets and Bitcoin cryptocurrency are weakly correlated at higher frequencies throughout the sample period, but the dependence of Bitcoin on the equity markets steadily increases at lower frequencies. Further, we construct the wavelet-based Granger causality test at different time scales to provide additional support to our connectedness results. Our findings provide important implications for policymakers, portfolio managers, and investors who are invited to take into account the dynamic linkages between Bitcoin and equity markets.

By considering a new form of dimensional reduction for noncommutative field theory, we show that the signature of spacetime may be changed. In particular, it is demonstrated that a temporal dimension can emerge from a purely Euclidean geometry. We suggest that this mechanism may hint at the origin of time in the fundamental theory of quantum gravity.

The importance for cosmology of the recently introduced ELKOs requires our deepest understanding of them and of all of their fundamental properties. Among these fundamental properties, a special one is causality: in the present paper, we show that causality is always preserved for ELKOs.

Causality is one of the most important properties to understand gravity theories. It gives us not only a method to confirm that the gravity theories are really consistent, but also gives implications about the properties which unknown fundamental physics should obey. We investigate the causality of three-dimensional (3D) gravity theories, which are considered to be important, by using the Shapiro time delay effect in the Shock wave geometry. One of such gravity theories is the Zwei-Dreibein Gravity (ZDG) theory, which is a consistent 3D gravity theory. In ZDG theory, the serious problems can be removed that have appeared in another important gravity theory called New Massive Gravity (NMG). We study whether the ZDG theory could preserve the causality without losing the above good properties and how the causality structure is related to the structure of the NMG theory.