Essentially finite vector bundle 1970-01-01
An essentially finite vector bundle is a specific type of vector bundle that arises in the context of algebraic geometry and differential geometry. While there isn’t a universally accepted definition across all mathematical disciplines, the term generally encapsulates the idea of a vector bundle that has a finite amount of "variation" in some sense.
Fundamental group scheme 1970-01-01
In algebraic geometry, the concept of a *fundamental group scheme* arises as an extension of the classical notion of the fundamental group in topology. It captures the idea of "loop" or "path" structures within a geometric object, such as a variety or more general scheme, but in a way that's suitable for the context of algebraic geometry.
Lefschetz hyperplane theorem 1970-01-01
The Lefschetz hyperplane theorem is a fundamental result in algebraic geometry and topology that relates the topology of a projective variety to that of its hyperplane sections. Specifically, it provides information about the cohomology groups of a projective variety and its hyperplane sections. To state the theorem more formally: Let \(X\) be a smooth projective variety of dimension \(n\) defined over an algebraically closed field.
Nakano vanishing theorem 1970-01-01
The Nakano vanishing theorem is a result in the field of algebraic geometry, specifically concerning the cohomology of coherent sheaves on projective varieties. It is closely related to the properties of vector bundles and their sections in the context of ample line bundles. The theorem essentially states that certain cohomology groups of coherent sheaves vanish under specific conditions.
Nori-semistable vector bundle 1970-01-01
A Nori-semistable vector bundle is a concept that arises in the context of algebraic geometry, particularly in the study of vector bundles over algebraic varieties. It is named after Mukai and Nori, who have contributed to the theory of stability of vector bundles. In the framework of vector bundles, the stability of a bundle can be understood in relation to how it behaves with respect to a given geometric context, particularly with respect to a projective curve or a variety.
Analysis of rhythmic variance 1970-01-01
Analysis of rhythmic variance refers to the examination and evaluation of variations in rhythmic patterns, often within the context of music, dance, or other forms of artistic expression, as well as in biological rhythms and physiological processes. Here are some potential contexts in which rhythmic variance might be analyzed: 1. **Musicology**: In music, rhythmic variance involves studying how rhythms change over time within a piece or across different compositions.
Bayesian structural time series 1970-01-01
Bayesian Structural Time Series (BSTS) is a framework used for modeling and forecasting time series data that incorporates both structural components and Bayesian methods. The BSTS framework is particularly useful for analyzing data with complex patterns, such as trends, seasonality, and irregularities, while also allowing for the incorporation of various types of uncertainty. ### Key Components of Bayesian Structural Time Series: 1. **Structural Components**: - **Trend**: Captures long-term movements in the data.
Bispectrum 1970-01-01
The bispectrum is a specific mathematical tool used in signal processing and statistical analysis to examine the relationships between different frequency components of a signal. It is a type of higher-order spectrum that goes beyond the traditional power spectrum, which only captures information about the power of individual frequency components. Mathematically, the bispectrum is defined as the Fourier transform of the third-order cumulant of a signal.
CARIACO Ocean Time Series Program 1970-01-01
The CARIACO Ocean Time Series Program is a long-term scientific study that focuses on the Caribbean Sea, particularly the region off the coast of Venezuela in the Cariaco Basin. Established in 1995, the program involves continuous monitoring and data collection aimed at understanding the ocean's physical, chemical, and biological processes.
Correlation function 1970-01-01
A correlation function is a statistical tool used to measure and describe the relationship between two or more variables, capturing how one variable may change in relation to another. It helps to assess the degree to which variables are correlated, meaning how much they move together or how one variable can predict the other. Correlation functions are widely used in various fields, including physics, signal processing, economics, and neuroscience. ### Types of Correlation Functions 1.
Decomposition of time series 1970-01-01
Decomposition of time series is a statistical technique used to analyze and understand the underlying components of a time series dataset. The main goal of this process is to separate the time series into its constituent parts so that each component can be studied and understood independently. Time series data typically exhibits four main components: 1. **Trend**: This component represents the long-term movement or direction in the data. It indicates whether the data values are increasing, decreasing, or remaining constant over time.
Divisia index 1970-01-01
The Divisia index is a method used to measure changes in economic variables, such as output or prices, over time while accounting for the contribution of individual components. It is particularly useful in the context of measuring real GDP or overall productivity because it provides a way to aggregate different goods and services into a single index that reflects changes in quantity and quality. The Divisia index is based on the concept of a weighted average, where the weights are derived from the quantities of the individual components in each period.
Dynamic mode decomposition 1970-01-01
Dynamic Mode Decomposition (DMD) is a data-driven technique used in the analysis of dynamical systems, particularly for identifying patterns and extracting coherent structures from time-series data. It was introduced as a method for analyzing fluid flows and has since found applications in various fields such as engineering, biology, finance, and more. ### Key Concepts: 1. **Data Representation**: DMD decomposes a set of snapshots of a dynamical system into modes that represent the underlying dynamics.
Safvet-beg Bašagić 1970-01-01
Safvet-beg Bašagić (1870-1934) was a prominent Bosnian Muslim writer, historian, and cultural activist from Bosnia and Herzegovina. He is best known for his contributions to the fields of literature, history, and cultural studies, particularly in relation to Bosnian heritage and identity.
Sine wave 1970-01-01
A sine wave is a mathematical curve that describes a smooth, periodic oscillation. It is one of the most fundamental waveforms in mathematics, physics, and engineering. The sine wave is characterized by its smooth and continuous shape, which resembles a regular, oscillating pattern.
Forecasting 1970-01-01
Forecasting is the process of making predictions about future events or trends based on historical data, analysis of current conditions, and the use of various modeling techniques. It is widely used in various fields, including business, economics, meteorology, finance, and supply chain management, among others. Key components of forecasting include: 1. **Data Collection**: Gather relevant data from past trends, patterns, and behaviors.
Hodrick–Prescott filter 1970-01-01
The Hodrick-Prescott (HP) filter is a mathematical tool used in macroeconomics and time series analysis to decompose a time series into a trend component and a cyclical component. It is particularly useful for analyzing economic data, such as GDP or other macroeconomic indicators, to separate the long-term trend from short-term fluctuations.
Journal of Time Series Analysis 1970-01-01
The Journal of Time Series Analysis is a peer-reviewed academic journal that focuses on the theory and application of time series analysis. It publishes original research articles, review papers, and methodological studies related to time series data, which are sequences of observations collected over time.
Lag operator 1970-01-01
The lag operator, often denoted as \( L \), is a mathematical operator used primarily in time series analysis to shift a time series back in time. Specifically, when applied to a time series variable, the lag operator \( L \) produces the values of that variable from previous time periods.
Long-range dependence 1970-01-01
Long-range dependence (LRD) is a statistical property of time series or stochastic processes characterized by correlations that decay more slowly than an exponential rate. In other words, past values in a process influence future values over long time horizons, leading to significant dependence among observations even when they are far apart in time.