Closure (computer science) - Closure (computer science) In programming languages, a closure is an abstraction representing a function, plus the lexical environment (see static scoping) in which the function was created. Closures are typically implemented with a special data structure that contains a pointer to the function code, plus a representation of the function's lexical environment (i.e., the set of available variables and their values) at the time when the closure was created. Closures typically appear in languages that allow functions to be "first-class" values --- in other words, such languages allow functions to be passed as arguments, returned from function calls, bound to variable names, etc., just like simpler types such as strings and integers. For example, in ML, the following code defines a function f that returns its.
Field (mathematics) - in which fields can be contained in each other. See Field theory (mathematics) for more. Table of contents showTocToggle("show","hide") 1 Definition 2 Examples of Fields 3 Some first theorems 4 Constructing new fields from given ones 5 History 6 Related topics Definition A field is a commutative ring (F, +, *) such that 0 does not equal 1 and all elements of F except 0 have a multiplicative inverse. Spelled out, this means that the following hold: ; Closure of F under + and * : For all a,b belonging to F, both a + b and a * b belong to F (or more formally, + and * are binary operations on F); ; Both + and * are associative : For all a,b,c in F, a + (b +.
Field theory (mathematics) - was Emil Artin who first developed the relationship of groups and fields in great details during 1928-1942. Elementary Introduction The concept of fields was first used to prove that there is no general formula for the roots of real polynomials of degree higher than 4. The central concept of Galois theory is the algebraic extension of an underlying field. It is simply the smallest field containing the underlying field and a root of a polynomial. An algebraically closed field is a field in which every polynomial has a root. For instance, the field of algebraic numbers is the algebraic closure of the field of rational numbers and the field of complex numbers is the algebraic closure of the field of real numbers. Finite fields are used in coding theory. Again algebraic.
April 2003 - force and uniform pre-departure health screening in airports. Israeli forces assassinate three Palestinian militants in Gaza, including Nidal Salamah, a leader of the Popular Front for the Liberation of Palestine. The action prompts accusations that Israel is trying to sabotage the Palestinian government's attempts to transform itself. Mahmoud Abbas is confirmed as the first Palestinian Authority prime minister after winning a vote of confidence from the Palestinian legislature. The United States announces that it will be reducing its military presence in Saudi Arabia to a handful of advisors. Lynn Htun, suspected of being the head of the Fluffi Bunni computer cracker ring, is arrested in London. [1] Quebec premier-elect Jean Charest is sworn in and names his cabinet. [1] April 28, 2003 The World Health Organization announces that SARS has peaked.
Background and genesis of topos theory - truth-values, true and false. It is almost tautologous to say that the subsets of a given set X are the same as (just as good as) the functions on X to any such given two-element set: fix the 'first' element and make a subset Y correspond to the function sending Y there and its complement in X to the other element. Now sub-object classifiers can be found in sheaf theory. Still tautologously, though certainly more abstractly, for a topological space X there is a direct description of a sheaf on X that plays the role with respect to all sheaves of sets on X. In fact in terms of the space associated with a sheaf it is attractively described as the union of disjoint copies of each open set U of.
Binary operation - operation as well. More precisely, a binary operation on a set S is a binary function from S and S to S, in other words a function f from the Cartesian product S × S to S. Sometimes, especially in computer science, the term is used for any binary function. That f takes values in the same set S that provides its arguments is the property of closure. Binary operations are the keystone of algebraic structures studied in abstract algebra: they form part of groups, monoids, semigroups, ringss, and more. Most generally, a magma is a set together with any binary operation defined on it. Many binary operations of interest are commutative or associative. Many also have identity elements and inverse elements. Typical examples of binary operations are the addition and.
Clanking replicator - "von Neumann machines" after John von Neumann, who first rigorously studied the idea. This last term is less specific and also refers to a completely unrelated computer architecture proposed by von Neumann, so is perhaps not the best to use where accuracy is important. Von Neumann himself used the term "Universal Constructor." Table of contents showTocToggle("show","hide") 1 Basic concept 2 History of the concept 3 Clanking replicators in fiction 3.1 Other notable works containing clanking replicators 4 Prospects for implementation Basic concept Whilst such a machine violates no physical laws, and we already possess the basic technologies necessary for some of the more detailed proposed designs, constructing a clanking replicator is not considered to be of major economic interest at this time. A self-replicating machine would need to have the capacity.
September 2003 - Palestinian Islamic Jihad claimed responsibility for the attack.[1] Road map for peace: 'Quartet' urges Israel and Palestinians to do more to revive Middle East peace plan. Voicing "great concern" at recent Israeli and Palestinian attacks that have stalled the Middle East peace process, a high-level meeting of the diplomatic Quartet of the United Nations, United States, Russian Federation and European Union call on both sides to take immediate action to revive the Road map for peace. [1] [1] Iraq - Constitution: Secretary of State Colin Powell, responding to a rapid timetable self-rule demands from France (and others), states the United States would set a deadline of six months for Iraqi leaders working under the coalition occupation to produce a new constitution. The constitution would clear the way for elections and the.
Static scoping - Static scoping In computer science, static scoping, as opposed to dynamic scoping, is a way that the scope of certain variables is determined according to its position in program code. It is also called lexical scoping or lexically scoping. A variable is said to be lexically scoped if its scope is defined by the text of the program. For instance a variable named balance might be scoped to the inside of the body of one function. That variable is then guaranteed to have nothing to do with any other variable named balance anywhere else in the program, or indeed with the variable named balance in other calls to the same function. This allows programmers to guarantee that their private variables will not accidentally be accessed or altered by.
Subroutine - Subroutine In computer science, a subroutine (function, procedure, or subprogram) is a sequence of code which performs a specific task, as part of a larger program, and is grouped as one, or more, statement blocks; such code is sometimes collected into software libraries. Subroutines can be "called", this allows programs to access the subroutine repeatedly, without the subroutine's code having been written more than once. Table of contents showTocToggle("show","hide") 1 History 2 Technical Overview 3 C/C++ Examples 4 Ruby Example 5 Why use subprograms? 6 Local variables, recursion, and re-entrancy 7 Conventions 8 Related terms and clarification History The first use of subprograms was in assembly languages. Technical Overview A subprogram, as its name suggest, somehow behaves like a computer program. Typically, the caller waits for subprograms.
November 2003 - [1] Police in Turkey announce the arrest of a yet-unnamed man they state has admitted giving the order to suicide bombers to attack Beth Israel synagogue in Istanbul on November 15. [1] Luan Enjie, director of the National Aerospace Bureau of the People's Republic of China states that "By 2020, we will achieve visiting the moon." [1] Occupation of Iraq: A team of 8 Spanish intelligence agents is attacked south of Baghdad; 7 are killed and 1 wounded. [1] Two Japanese diplomats are killed near Tikrit. Two U.S. soldiers and a Colombian civilian contractor are killed in Baghdad. In Australia, the opposition Labor Party's finance spokesperson, Mark Latham, announces that he will contest the party leadership ballot on 2 December against the former leader Kim Beazley. Press reports place the two.
Liane Gabora - She is best known for her theory of the "Origin of the modern mind through conceptual closure." This built on her earlier work on "Autocatalytic closure in a cognitive system: A tentative scenario for the origin of culture." a discussion of her "conceptual closure" theory should go here She has contributed to the study of meme, cultural evolution and evolution of societies - and has focused strongly on the role of personal creativity, as opposed to memetic imitation or instruction, in differentiating modern human from prior hominid or modern ape culture. In particular, she seems to follow feminist economists and green economists in making a very strong, indeed pivotal, distinction between creative "enterprise", invention, art or "individual capital" and imitative "meme", rule, social category or "instructional capital". Her view contrasts with.
List of mathematical topics - G-I - J-L - M-O - P-R - S-U - V-Z 0-9 1/f noise -- 2 to the power of C -- 3-satisfiability -- 3-sphere -- 3D projection -- 10-sided dice A Abacus -- abc Conjecture -- Abel, Niels Henrik -- Abel Prize -- Abelian -- Abelian and tauberian theorems -- Abelian category -- Abelian extension -- Abelian group -- Abelian variety -- Abel-Ruffini theorem -- Abel's theorem -- Abraham, Ralph -- Absolute continuity -- Absolute value -- Absorption law -- Abstract algebra -- Abstract interpretation -- Abstract structure -- Abundance -- Abundant number -- Acceleration -- Acceptance angle -- Ackermann function -- Ackermann, Wilhelm -- Ackermann steering geometry -- Active and passive transformation -- Actuarial science -- Addition -- Addition in N -- Additive category -- Additive function -- Additive.
List of mathematical topics (G-I) - -- Hieroglyphics -- Higher-order function -- Highest averages method -- Highly composite number -- Hilbert, David -- Hilbert cube -- Hilbert matrix -- Hilbert space -- Hilbert's basis theorem -- Hilbert's Nullstellensatz -- Hilbert's paradox of the Grand Hotel -- Hilbert's problems -- Hilbert's seventh problem -- Hilbert's tenth problem -- Hilbert's third problem -- Hipparchus -- Hironaka, Heisuke -- Histogram -- History of large numbers -- History of mathematics -- History of the separation axioms -- Hlavaty, Vaclav -- Hoare, C.A.R -- Hodge, W.V.D -- Hodge conjecture -- Hodge dual -- HOL -- Hölder, Otto -- Hölder's inequality -- Holomorphic -- Holomorphic function -- Homeomorphic -- Homeomorphism -- Homogeneity -- Homogeneous co-ordinates -- Homogeneous space -- Homological algebra -- Homology -- Homology group -- Homomorphism -- Homotopy -- Hopf algebra.
List of basic discrete mathematics topics - equation Quadratic equation Mathematical relations Binary relation Mathematical relation Reflexive relation Reflexive property of equality Symmetric relation Symmetric property of equality Antisymmetric relation Transitive Transitivity Transitive closure Transitive property of equality Equivalence and identity Equivalence relation Equivalence class Equality (mathematics) Inequation Inequality Similarity (mathematics) Congruence (geometry) Equation Identity Identity element Identity function Substitution property of equality Graphing equivalence Extensionality Uniqueness quantification Mathematical phraseology If and only if (iff) Necessary and sufficient Sufficient condition Distinct Difference Absolute value Up to Normal form Without loss of generality Vacuous truth Contradiction, Reductio ad absurdum Counterexample Table of mathematical symbols Combinatorics Permutation Combination Factorial Empty product Pascal's triangle Probability Average Expectation Discrete random variable Propositional logic Logical operator Truth table De Morgan's laws Open sentence List of topics in logic Mathematical disciplines For further reading.
Integer (computer science) - Integer (computer science) This article should be merged with computer numbering formats. In computer science, the term integer is used to refer to any data type which can represent some subset of the mathematical integers. These are also known as integral data types. Table of contents showTocToggle("show","hide") 1 Value and Representation 2 Common integral data types 3 Pointers 4 Bytes and Octets 5 Words Value and Representation The value of a datum with an integral type is the mathematical integer that it corresponds to. The representation of this datum is the way the value is stored in the computer's memory. Integral types may be unsigned (capable of representing only nonnegative integers) or signed (capable of representing negative integers as well). The most common representation of a positive.
Inheritance (computer science) - Inheritance (computer science) In computer science, inheritance creates an is a relationship between data structures. Thus the logic proposition "Socrates is a man" states that the Socrates also has the attributes of other men. Currently Java and C++, among others, allow this type of proposition to be stated directly in the respective languages by using the Java construct subclass name extends class name, or the C++ notation subclass : class name. Inheritance is fundamentally different than composition, where the relationship is has a instead of is a, for example, "a car has a motor". Inheritance can also be used in interfaces to give the appearance of being whatever - for example if we have an such an interface below, these could all have a "makeNoise();" method. Mammal.
Isolation (computer science) - Isolation (computer science) In database systems, "isolation" is a property that the changes made by an operation are not visible to other simultaneous operations on the system until its completion. This is one of the ACID properties..
VEGA computer algebra system - VEGA computer algebra system Vega is a system for manipulating discrete mathematical structures. The ongoing project is located at the Department of Theoretical Computer Science at IMFM. See http://vega.ijp.si/Htmldoc/vega03.html.
Information science glossary of terms - Information science glossary of terms An abstract is a brief set of statements that summarize, classifies, evaluates, or describes the important points of a text, particularly a journal article. An abstract is typically found on the first page of a scholarly article. Because an abstract summarizes an article, it is very useful for either browsing or keyword searching. An annotation (noun) is an explanatory or critical note or commentary. Annotation (verb) is the process of adding an explanatory or critical note or commentary to a text. Reference lists are often annotated with comments about what each resource covered and how useful it was. An appendix is a group of supplementary material appended to a text. It is usually related to the material in the main part of.
