Logarithmic derivativeIn mathematics, specifically in calculus and complex analysis, the logarithmic derivative of a function f is defined by the formula where is the derivative of f. Intuitively, this is the infinitesimal relative change in f; that is, the infinitesimal absolute change in f, namely scaled by the current value of f. When f is a function f(x) of a real variable x, and takes real, strictly positive values, this is equal to the derivative of ln(f), or the natural logarithm of f.
Elliptic curveIn mathematics, an elliptic curve is a smooth, projective, algebraic curve of genus one, on which there is a specified point O. An elliptic curve is defined over a field K and describes points in K^2, the Cartesian product of K with itself. If the field's characteristic is different from 2 and 3, then the curve can be described as a plane algebraic curve which consists of solutions (x, y) for: for some coefficients a and b in K. The curve is required to be non-singular, which means that the curve has no cusps or self-intersections.
Total derivativeIn mathematics, the total derivative of a function f at a point is the best linear approximation near this point of the function with respect to its arguments. Unlike partial derivatives, the total derivative approximates the function with respect to all of its arguments, not just a single one. In many situations, this is the same as considering all partial derivatives simultaneously. The term "total derivative" is primarily used when f is a function of several variables, because when f is a function of a single variable, the total derivative is the same as the ordinary derivative of the function.
Wirtinger derivativesIn complex analysis of one and several complex variables, Wirtinger derivatives (sometimes also called Wirtinger operators), named after Wilhelm Wirtinger who introduced them in 1927 in the course of his studies on the theory of functions of several complex variables, are partial differential operators of the first order which behave in a very similar manner to the ordinary derivatives with respect to one real variable, when applied to holomorphic functions, antiholomorphic functions or simply differentiabl
QuadricIn mathematics, a quadric or quadric surface (quadric hypersurface in higher dimensions), is a generalization of conic sections (ellipses, parabolas, and hyperbolas). It is a hypersurface (of dimension D) in a (D + 1)-dimensional space, and it is defined as the zero set of an irreducible polynomial of degree two in D + 1 variables; for example, D = 1 in the case of conic sections. When the defining polynomial is not absolutely irreducible, the zero set is generally not considered a quadric, although it is often called a degenerate quadric or a reducible quadric.
Level setIn mathematics, a level set of a real-valued function f of n real variables is a set where the function takes on a given constant value c, that is: When the number of independent variables is two, a level set is called a level curve, also known as contour line or isoline; so a level curve is the set of all real-valued solutions of an equation in two variables x_1 and x_2. When n = 3, a level set is called a level surface (or isosurface); so a level surface is the set of all real-valued roots of an equation in three variables x_1, x_2 and x_3.
Anna SuiAnna Sui (; born August 4, 1964) is an American fashion designer. She was named one of the "Top 5 Fashion Icons of the Decade", and in 2009 earned the Geoffrey Beene Lifetime Achievement Award from the Council of Fashion Designers of America (CFDA), joining the ranks of Yves Saint Laurent, Giorgio Armani, Ralph Lauren, and Diane von Furstenberg. Her brand categories include several fashion lines, footwear, cosmetics, fragrances, eyewear, jewelry, accessories, home goods and a gifts line.
.ch.ch is the country code top-level domain (ccTLD) for Switzerland in the Domain Name System of the Internet. Made available in 1987, only two years after .com, it is administered by SWITCH Information Technology Services. The domain ch, as with other ccTLDs, is based on the ISO 3166-2 code for Switzerland derived from Confoederatio Helvetica (Helvetic Confederation), the Latin name for the country, which was used because of its neutrality with regard to the four official languages of Switzerland.
Anna KomneneAnna Komnene (Ánna Komnēnḗ; 1 December 1083 – 1153), commonly Latinized as Anna Comnena, was a Byzantine princess and author of the Alexiad, an account of the reign of her father, the Byzantine emperor, Alexios I Komnenos. The Alexiad is the most important primary source of Byzantine history of the late 11th and early 12th centuries. Although she is best known as the author of the Alexiad, Anna played an important part in the politics of the time and attempted to depose her brother, John II Komnenos, as emperor and seize the throne herself.
FC VSS KošiceFC VSS Košice, formerly 1. FC Košice, was a Slovak football club based in Košice which played in the Slovak 2. Liga during the 2016–17 season. The club officially ceased operations on 27 July 2017. The club, founded in 1903, has won the Slovak League twice, the Slovak Cup five times and the Czechoslovak Cup once. The most successful eras of the club were in the 1970s and 1990s which they spent mostly in the top tier of Czechoslovak and Slovak Football. Two of the UEFA Euro 1976 champions namely Dušan Galis and Jaroslav Pollák played for Košice.
20222022 saw the removal of nearly all COVID-19 restrictions and the reopening of international borders in most countries, and the global rollout of COVID-19 vaccines continued. The global economic recovery from the pandemic continued, though many countries experienced an ongoing inflation surge; in response, many central banks raised their interest rates to landmark levels. The world population reached eight billion people in 2022, though the year also witnessed numerous natural disasters, including two devastating Atlantic hurricanes (Fiona and Ian), and the most powerful volcano eruption of the century so far.
RAF JurbyRoyal Air Force Station Jurby or more simply RAF Jurby is a former Royal Air Force station built in the north west of the Isle of Man. It was opened in 1939 on of land acquired by the Air Ministry in 1937, under the control of No. 29 Group, RAF. During the Second World War the station was used for training as No. 5 Armament Training Station, No. 5 Air Observer School, No. 5 Bombing & Gunnery School and the No. 5 Air Navigation & Bombing School. In addition RAF Jurby also played host to a variety of operational squadrons.
