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Gosper's Algorithm
In mathematics, Gosper's algorithm, due to Bill Gosper, is a procedure for finding sums of hypergeometric terms that are themselves hypergeometric terms. That is: suppose one has ''a''(1) + ... + ''a''(''n'') = ''S''(''n'') − ''S''(0), where ''S''(''n'') is a hypergeometric term (i.e., ''S''(''n'' + 1)/''S''(''n'') is a rational function of ''n''); then necessarily ''a''(''n'') is itself a hypergeometric term, and given the formula for ''a''(''n'') Gosper's algorithm finds that for ''S''(''n''). Outline of the algorithm Step 1: Find a polynomial ''p'' such that, writing ''b''(''n'') = ''a''(''n'')/''p''(''n''), the ratio ''b''(''n'')/''b''(''n'' − 1) has the form ''q''(''n'')/''r''(''n'') where ''q'' and ''r'' are polynomials and no ''q''(''n'') has a nontrivial factor with ''r''(''n'' + ''j'') for ''j'' = 0, 1, 2, ... . (This is always possible, whether or not the series is summable in cl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mathematics
Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics with the major subdisciplines of number theory, algebra, geometry, and analysis, respectively. There is no general consensus among mathematicians about a common definition for their academic discipline. Most mathematical activity involves the discovery of properties of abstract objects and the use of pure reason to prove them. These objects consist of either abstractions from nature orin modern mathematicsentities that are stipulated to have certain properties, called axioms. A ''proof'' consists of a succession of applications of deductive rules to already established results. These results include previously proved theorems, axioms, andin case of abstraction from naturesome basic properties that are considered true starting points of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bill Gosper
Ralph William Gosper Jr. (born April 26, 1943), known as Bill Gosper, is an American mathematician and programmer. Along with Richard Greenblatt, he may be considered to have founded the hacker community, and he holds a place of pride in the Lisp community. The Gosper curve and the Gosper's algorithm are named after him. Becoming a hacker In high school, Gosper was interested in model rockets until one of his friends was injured in a rocketry accident and contracted a fatal brain infection.. Gosper enrolled in MIT in 1961, and he received his bachelor's degree in mathematics from MIT in 1965 despite becoming disaffected with the mathematics department because of their anti-computer attitude. In his second year at MIT, Gosper took a programming course from John McCarthy and became affiliated with the MIT AI Lab. His contributions to computational mathematics include HAKMEM and the MIT Maclisp system. He made major contributions to Macsyma, Project MAC's computer algebr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypergeometric Identities
In mathematics, hypergeometric identities are equalities involving sums over hypergeometric terms, i.e. the coefficients occurring in hypergeometric series. These identities occur frequently in solutions to combinatorial problems, and also in the analysis of algorithms. These identities were traditionally found 'by hand'. There exist now several algorithms which can find and ''prove'' all hypergeometric identities. Examples : \sum_^ = 2^ : \sum_^ ^2 = : \sum_^ k = n2^ : \sum_^ i = (n+1)- Definition There are two definitions of hypergeometric terms, both used in different cases as explained below. See also hypergeometric series. A term ''tk'' is a hypergeometric term if : \frac is a rational function in ''k''. A term ''F(n,k)'' is a hypergeometric term if : \frac is a rational function in ''k''. There exist two types of sums over hypergeometric terms, the definite and indefinite sums. A definite sum is of the form : \sum_ t_k. The indefinite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rational Function
In mathematics, a rational function is any function that can be defined by a rational fraction, which is an algebraic fraction such that both the numerator and the denominator are polynomials. The coefficients of the polynomials need not be rational numbers; they may be taken in any field ''K''. In this case, one speaks of a rational function and a rational fraction ''over K''. The values of the variables may be taken in any field ''L'' containing ''K''. Then the domain of the function is the set of the values of the variables for which the denominator is not zero, and the codomain is ''L''. The set of rational functions over a field ''K'' is a field, the field of fractions of the ring of the polynomial functions over ''K''. Definitions A function f(x) is called a rational function if and only if it can be written in the form : f(x) = \frac where P\, and Q\, are polynomial functions of x\, and Q\, is not the zero function. The domain of f\, is the set of all valu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
A K Peters Ltd
A K Peters, Ltd. was a publisher of scientific and technical books, specializing in mathematics and in computer graphics, robotics, and other fields of computer science. They published the journals ''Experimental Mathematics'' and the '' Journal of Graphics Tools'', as well as mathematics books geared to children. Background Klaus Peters wrote a doctoral dissertation on complex manifolds at the University of Erlangen in 1962, supervised by Reinhold Remmert. He then joined Springer Verlag, becoming their first specialist mathematics editor. As a Springer director from 1971, he hired Alice Merker for Springer New York: they were married that year, and moved to Heidelberg. Leaving Springer, they founded Birkhäuser Boston in 1979; Birkhäuser ran into financial difficulties, and was taken over by Springer. Klaus and Alice then spent a period running a Boston office for Harcourt Brace Jovanovich and their imprint Academic Press. With the takeover of Harcourt Brace Jovanovich by Ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilf–Zeilberger Pair
In mathematics, specifically combinatorics, a Wilf–Zeilberger pair, or WZ pair, is a pair of functions that can be used to certify certain combinatorial identities. WZ pairs are named after Herbert S. Wilf and Doron Zeilberger, and are instrumental in the evaluation of many sums involving binomial coefficients, factorials, and in general any hypergeometric series. A function's WZ counterpart may be used to find an equivalent and much simpler sum. Although finding WZ pairs by hand is impractical in most cases, Gosper's algorithm provides a sure method to find a function's WZ counterpart, and can be implemented in a symbolic manipulation program. Definition Two functions ''F'' and&n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Petkovšek's Algorithm
Petkovšek's algorithm (also Hyper) is a computer algebra algorithm that computes a basis of hypergeometric terms solution of its input linear recurrence equation with polynomial coefficients. Equivalently, it computes a first order right factor of linear difference operators with polynomial coefficients. This algorithm was developed by Marko Petkovšek in his PhD-thesis 1992. The algorithm is implemented in all the major computer algebra systems. Gosper-Petkovšek representation Let \mathbb be a field of characteristic zero. A nonzero sequence y(n) is called hypergeometric if the ratio of two consecutive terms is rational, i.e. y (n+1) /y(n) \in \mathbb(n). The Petkovšek algorithm uses as key concept that this rational function has a specific representation, namely the ''Gosper-Petkovšek normal form''. Let r(n) \in \mathbb /math> be a nonzero rational function. Then there exist monic polynomials a, b, c \in \mathbb /math> and 0 \neq z \in \mathbb such that r(n) = z \frac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macsyma
Macsyma (; "Project MAC's SYmbolic MAnipulator") is one of the oldest general-purpose computer algebra systems still in wide use. It was originally developed from 1968 to 1982 at MIT's Project MAC. In 1982, Macsyma was licensed to Symbolics and became a commercial product. In 1992, Symbolics Macsyma was spun off to Macsyma, Inc., which continued to develop Macsyma until 1999. That version is still available for Microsoft's Windows XP operating system. The 1982 version of MIT Macsyma remained available to academics and US government agencies, and it is distributed by the US Department of Energy (DOE). That version, DOE Macsyma, was maintained by Bill Schelter. Under the name of Maxima, it was released under the GPL in 1999, and remains under active maintenance. Development The project was initiated in July, 1968 by Carl Engelman, William A. Martin (front end, expression display, polynomial arithmetic) and Joel Moses (simplifier, indefinite integration: heuristic/Risch). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stanford Artificial Intelligence Laboratory
Stanford University has many centers and institutes dedicated to the study of various specific topics. These centers and institutes may be within a department, within a school but across departments, an independent laboratory, institute or center reporting directly to the dean of research and outside any school, or semi-independent of the university itself. Independent laboratories, institutes and centers These report directly to the vice-provost and dean of research and are outside any school though any faculty involved in them must belong to a department in one of the schools. These include Bio-X and Spectrum in the area of Biological and Life Sciences; Precourt Institute for Energy and Woods Institute for the Environment in the Environmental Sciences area; the Center for Advanced Study in the Behavioral Sciences (CASBS), the Center for the Study of Language and Information (CSLI) (see below), Freeman Spogli Institute for International Studies (FSI) (see below), Human-Sciences ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proceedings Of The National Academy Of Sciences Of The United States Of America
''Proceedings of the National Academy of Sciences of the United States of America'' (often abbreviated ''PNAS'' or ''PNAS USA'') is a peer-reviewed multidisciplinary scientific journal. It is the official journal of the National Academy of Sciences, published since 1915, and publishes original research, scientific reviews, commentaries, and letters. According to ''Journal Citation Reports'', the journal has a 2021 impact factor of 12.779. ''PNAS'' is the second most cited scientific journal, with more than 1.9 million cumulative citations from 2008 to 2018. In the mass media, ''PNAS'' has been described variously as "prestigious", "sedate", "renowned" and "high impact". ''PNAS'' is a delayed open access journal, with an embargo period of six months that can be bypassed for an author fee (hybrid open access). Since September 2017, open access articles are published under a Creative Commons license. Since January 2019, ''PNAS'' has been online-only, although print issues are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Algebra
In mathematics and computer science, computer algebra, also called symbolic computation or algebraic computation, is a scientific area that refers to the study and development of algorithms and software for manipulating mathematical expressions and other mathematical objects. Although computer algebra could be considered a subfield of scientific computing, they are generally considered as distinct fields because scientific computing is usually based on numerical computation with approximate floating point numbers, while symbolic computation emphasizes ''exact'' computation with expressions containing variables that have no given value and are manipulated as symbols. Software applications that perform symbolic calculations are called ''computer algebra systems'', with the term ''system'' alluding to the complexity of the main applications that include, at least, a method to represent mathematical data in a computer, a user programming language (usually different from the lang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
