|
Felice Casorati (mathematician)
Felice Casorati (17 December 1835 – 11 September 1890) was an Italian mathematician who studied at the University of Pavia. He was born in Pavia and died in Casteggio. He is best known for the Casorati–Weierstrass theorem in complex analysis. The theorem, named for Casorati and Karl Theodor Wilhelm Weierstrass, describes the remarkable behavior of holomorphic functions near essential singularities, which is that every holomorphic function gets values from any complex neighbourhood, in any neighbourhood of the singularity. The Casorati matrix is useful in the study of linear difference equations, just as the Wronskian is useful with linear differential equations. It is calculated based on n functions of the single input variable. Works * , available at Gallica (also aGDZ. Freely available copies of volume 1 of his best-known monograph A monograph is a specialist work of writing (in contrast to reference works) or exhibition on a single subject or an aspect of a subjec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pavia
Pavia (, , , ; la, Ticinum; Medieval Latin: ) is a town and comune of south-western Lombardy in northern Italy, south of Milan on the lower Ticino river near its confluence with the Po. It has a population of c. 73,086. The city was the capital of the Ostrogothic Kingdom from 540 to 553, of the Kingdom of the Lombards from 572 to 774, of the Kingdom of Italy from 774 to 1024 and seat of the Visconti court from 1365 to 1413. Pavia is the capital of the fertile province of Pavia, which is known for a variety of agricultural products, including wine, rice, cereals, and dairy products. Although there are a number of industries located in the suburbs, these tend not to disturb the peaceful atmosphere of the town. It is home to the ancient University of Pavia (founded in 1361 and recognized in 2022 by the Times Higher Education among the top 10 in Italy and among the 300 best in the world), which together with the IUSS (Institute for Advanced Studies of Pavia), Ghislieri College, B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Essential Singularity
In complex analysis, an essential singularity of a function is a "severe" singularity near which the function exhibits odd behavior. The category ''essential singularity'' is a "left-over" or default group of isolated singularities that are especially unmanageable: by definition they fit into neither of the other two categories of singularity that may be dealt with in some manner – removable singularities and poles. In practice some include non-isolated singularities too; those do not have a residue. Formal description Consider an open subset U of the complex plane \mathbb. Let a be an element of U, and f\colon U\setminus\\to \mathbb a holomorphic function. The point a is called an ''essential singularity'' of the function f if the singularity is neither a pole nor a removable singularity. For example, the function f(z)=e^ has an essential singularity at z=0. Alternative descriptions Let \;a\; be a complex number, assume that f(z) is not defined at \;a\; but is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
19th-century Italian Mathematicians
The 19th (nineteenth) century began on 1 January 1801 ( MDCCCI), and ended on 31 December 1900 ( MCM). The 19th century was the ninth century of the 2nd millennium. The 19th century was characterized by vast social upheaval. Slavery was abolished in much of Europe and the Americas. The First Industrial Revolution, though it began in the late 18th century, expanding beyond its British homeland for the first time during this century, particularly remaking the economies and societies of the Low Countries, the Rhineland, Northern Italy, and the Northeastern United States. A few decades later, the Second Industrial Revolution led to ever more massive urbanization and much higher levels of productivity, profit, and prosperity, a pattern that continued into the 20th century. The Islamic gunpowder empires fell into decline and European imperialism brought much of South Asia, Southeast Asia, and almost all of Africa under colonial rule. It was also marked by the collapse of the large ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1890 Deaths
Year 189 ( CLXXXIX) was a common year starting on Wednesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Silanus and Silanus (or, less frequently, year 942 ''Ab urbe condita''). The denomination 189 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Roman Empire * Plague (possibly smallpox) kills as many as 2,000 people per day in Rome. Farmers are unable to harvest their crops, and food shortages bring riots in the city. China * Liu Bian succeeds Emperor Ling, as Chinese emperor of the Han Dynasty. * Dong Zhuo has Liu Bian deposed, and installs Emperor Xian as emperor. * Two thousand eunuchs in the palace are slaughtered in a violent purge in Luoyang, the capital of Han. By topic Arts and sciences * Galen publishes his ''"Treatise on the various temperaments"'' (aka '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1835 Births
Events January–March * January 7 – anchors off the Chonos Archipelago on her second voyage, with Charles Darwin on board as naturalist. * January 8 – The United States public debt contracts to zero, for the only time in history. * January 24 – Malê Revolt: African slaves of Yoruba Muslim origin revolt in Salvador, Bahia. * January 26 – Queen Maria II of Portugal marries Auguste de Beauharnais, 2nd Duke of Leuchtenberg, in Lisbon; he dies only two months later. * January 26 – Saint Paul's in Macau largely destroyed by fire after a typhoon hits. * January 30 – An assassination is attempted against United States President Andrew Jackson in the United States Capitol (the first assassination attempt against a President of the United States). * February 1 – Slavery is abolished in Mauritius. * February 20 – 1835 Concepción earthquake: Concepción, Chile, is destroyed by an earthquake; the resulting tsunami destroys the neighboring city of Talcahua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Monograph
A monograph is a specialist work of writing (in contrast to reference works) or exhibition on a single subject or an aspect of a subject, often by a single author or artist, and usually on a scholarly subject. In library cataloging, ''monograph'' has a broader meaning—that of a nonserial publication complete in one volume (book) or a definite number of volumes. Thus it differs from a serial or periodical publication such as a magazine, academic journal, or newspaper. In this context only, books such as novels are considered monographs.__FORCETOC__ Academia The English term "monograph" is derived from modern Latin "monographia", which has its root in Greek. In the English word, "mono-" means "single" and "-graph" means "something written". Unlike a textbook, which surveys the state of knowledge in a field, the main purpose of a monograph is to present primary research and original scholarship ascertaining reliable credibility to the required recipient. This research is prese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linear Differential Equations
In mathematics, a linear differential equation is a differential equation that is defined by a linear polynomial in the unknown function and its derivatives, that is an equation of the form :a_0(x)y + a_1(x)y' + a_2(x)y'' \cdots + a_n(x)y^ = b(x) where and are arbitrary differentiable functions that do not need to be linear, and are the successive derivatives of an unknown function of the variable . Such an equation is an ordinary differential equation (ODE). A ''linear differential equation'' may also be a linear partial differential equation (PDE), if the unknown function depends on several variables, and the derivatives that appear in the equation are partial derivatives. A linear differential equation or a system of linear equations such that the associated homogeneous equations have constant coefficients may be solved by quadrature, which means that the solutions may be expressed in terms of integrals. This is also true for a linear equation of order one, with non-con ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wronskian
In mathematics, the Wronskian (or Wrońskian) is a determinant introduced by and named by . It is used in the study of differential equations, where it can sometimes show linear independence in a set of solutions. Definition The Wronskian of two differentiable functions and is . More generally, for real- or complex-valued functions , which are times differentiable on an interval , the Wronskian as a function on is defined by W(f_1, \ldots, f_n) (x)= \begin f_1(x) & f_2(x) & \cdots & f_n(x) \\ f_1'(x) & f_2'(x) & \cdots & f_n' (x)\\ \vdots & \vdots & \ddots & \vdots \\ f_1^(x)& f_2^(x) & \cdots & f_n^(x) \end,\quad x\in I. That is, it is the determinant of the matrix constructed by placing the functions in the first row, the first derivative of each function in the second row, and so on through the th derivative, thus forming a square matrix. When the functions are solutions of a linear differential equation, the Wronskian can be found explicitly using Abel's ident ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recurrence Relation
In mathematics, a recurrence relation is an equation according to which the nth term of a sequence of numbers is equal to some combination of the previous terms. Often, only k previous terms of the sequence appear in the equation, for a parameter k that is independent of n; this number k is called the ''order'' of the relation. If the values of the first k numbers in the sequence have been given, the rest of the sequence can be calculated by repeatedly applying the equation. In ''linear recurrences'', the th term is equated to a linear function of the k previous terms. A famous example is the recurrence for the Fibonacci numbers, F_n=F_+F_ where the order k is two and the linear function merely adds the two previous terms. This example is a linear recurrence with constant coefficients, because the coefficients of the linear function (1 and 1) are constants that do not depend on n. For these recurrences, one can express the general term of the sequence as a closed-form expression o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neighbourhood (mathematics)
In topology and related areas of mathematics, a neighbourhood (or neighborhood) is one of the basic concepts in a topological space. It is closely related to the concepts of open set and interior. Intuitively speaking, a neighbourhood of a point is a set of points containing that point where one can move some amount in any direction away from that point without leaving the set. Definitions Neighbourhood of a point If X is a topological space and p is a point in X, then a of p is a subset V of X that includes an open set U containing p, p \in U \subseteq V \subseteq X. This is also equivalent to the point p \in X belonging to the topological interior of V in X. The neighbourhood V need be an open subset X, but when V is open in X then it is called an . Some authors have been known to require neighbourhoods to be open, so it is important to note conventions. A set that is a neighbourhood of each of its points is open since it can be expressed as the union of open sets ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holomorphic Function
In mathematics, a holomorphic function is a complex-valued function of one or more complex variables that is complex differentiable in a neighbourhood of each point in a domain in complex coordinate space . The existence of a complex derivative in a neighbourhood is a very strong condition: it implies that a holomorphic function is infinitely differentiable and locally equal to its own Taylor series (''analytic''). Holomorphic functions are the central objects of study in complex analysis. Though the term ''analytic function'' is often used interchangeably with "holomorphic function", the word "analytic" is defined in a broader sense to denote any function (real, complex, or of more general type) that can be written as a convergent power series in a neighbourhood of each point in its domain. That all holomorphic functions are complex analytic functions, and vice versa, is a major theorem in complex analysis. Holomorphic functions are also sometimes referred to as ''regular fu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
