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List Of Algebraic Constructions
An algebraic construction is a method by which an algebraic entity is defined or derived from another. Instances include: * Cayley–Dickson construction * Proj construction * Grothendieck group * Gelfand–Naimark–Segal construction * Ultraproduct * ADHM construction * Burnside ring * Simplicial set * Fox derivative * Mapping cone (homological algebra) * Prym variety * Todd class * Adjunction (field theory) * Vaughan Jones construction * Strähle construction * Coset construction * Plus construction * Algebraic K-theory * Gelfand–Naimark–Segal construction * Stanley–Reisner ring construction * Quotient ring construction * Ward's twistor construction * Hilbert symbol * Hilbert's arithmetic of ends * Colombeau's construction * Vector bundle * Integral monoid ring construction * Integral group ring construction * Category of Eilenberg–Moore algebras * Kleisli category * Adjunction (field theory) * Lindenbaum–Tarski algebra In mathematical logic, the Linden ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algebra
Algebra () is one of the broad areas of mathematics. Roughly speaking, algebra is the study of mathematical symbols and the rules for manipulating these symbols in formulas; it is a unifying thread of almost all of mathematics. Elementary algebra deals with the manipulation of variables (commonly represented by Roman letters) as if they were numbers and is therefore essential in all applications of mathematics. Abstract algebra is the name given, mostly in education, to the study of algebraic structures such as groups, rings, and fields (the term is no more in common use outside educational context). Linear algebra, which deals with linear equations and linear mappings, is used for modern presentations of geometry, and has many practical applications (in weather forecasting, for example). There are many areas of mathematics that belong to algebra, some having "algebra" in their name, such as commutative algebra, and some not, such as Galois theory. The word ''algebra'' is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plus Construction
In mathematics, the plus construction is a method for simplifying the fundamental group of a space without changing its homology and cohomology groups. Explicitly, if X is a based connected CW complex and P is a perfect normal subgroup of \pi_1(X) then a map f\colon X \to Y is called a +-construction relative to P if f induces an isomorphism on homology, and P is the kernel of \pi_1(X) \to \pi_1(Y).Charles Weibel, ''An introduction to algebraic K-theory'' IV, Definition 1.4.1 The plus construction was introduced by , and was used by Daniel Quillen to define algebraic K-theory. Given a perfect normal subgroup of the fundamental group of a connected CW complex X, attach two-cells along loops in X whose images in the fundamental group generate the subgroup. This operation generally changes the homology of the space, but these changes can be reversed by the addition of three-cells. The most common application of the plus construction is in algebraic K-theory. If R is a unital r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lindenbaum–Tarski Algebra
In mathematical logic, the Lindenbaum–Tarski algebra (or Lindenbaum algebra) of a logical theory ''T'' consists of the equivalence classes of sentences of the theory (i.e., the quotient, under the equivalence relation ~ defined such that ''p'' ~ ''q'' exactly when ''p'' and ''q'' are provably equivalent in ''T''). That is, two sentences are equivalent if the theory ''T'' proves that each implies the other. The Lindenbaum–Tarski algebra is thus the quotient algebra obtained by factoring the algebra of formulas by this congruence relation. The algebra is named for logicians Adolf Lindenbaum and Alfred Tarski. It was first introduced by Tarski in 1935 as a device to establish correspondence between classical propositional calculus and Boolean algebras. The Lindenbaum–Tarski algebra is considered the origin of the modern algebraic logic.; here: pages 1-2 Operations The operations in a Lindenbaum–Tarski algebra ''A'' are inherited from those in the underlying theory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kleisli Category
In category theory, a Kleisli category is a category (mathematics), category naturally associated to any monad (category theory), monad ''T''. It is equivalent to the category of free Monad (category theory)#Algebras for a monad, ''T''-algebras. The Kleisli category is one of two extremal solutions to the question ''Does every monad arise from an Adjunction (category theory), adjunction?'' The other extremal solution is the Eilenberg–Moore category. Kleisli categories are named for the mathematician Heinrich Kleisli. Formal definition Let ⟨''T'', ''η'', ''μ''⟩ be a monad (category theory), monad over a category ''C''. The Kleisli category of ''C'' is the category ''C''''T'' whose objects and morphisms are given by :\begin\mathrm() &= \mathrm(), \\ \mathrm_(X,Y) &= \mathrm_(X,TY).\end That is, every morphism ''f: X → T Y'' in ''C'' (with codomain ''TY'') can also be regarded as a morphism in ''C''''T'' (but with codomain ''Y''). Composition of morphisms in ''C''''T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eilenberg–Moore Algebra
In category theory, a branch of mathematics, a monad (also triple, triad, standard construction and fundamental construction) is a monoid in the category of endofunctors. An endofunctor is a functor mapping a category to itself, and a monad is an endofunctor together with two natural transformations required to fulfill certain coherence conditions. Monads are used in the theory of pairs of adjoint functors, and they generalize closure operators on partially ordered sets to arbitrary categories. Monads are also useful in the theory of datatypes and in functional programming languages, allowing languages with non-mutable states to do things such as simulate for-loops; see Monad (functional programming). Introduction and definition A monad is a certain type of endofunctor. For example, if F and G are a pair of adjoint functors, with F left adjoint to G, then the composition G \circ F is a monad. If F and G are inverse functors, the corresponding monad is the identity functor. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integral Group Ring
In algebra, a group ring is a free module and at the same time a ring, constructed in a natural way from any given ring and any given group. As a free module, its ring of scalars is the given ring, and its basis is the set of elements of the given group. As a ring, its addition law is that of the free module and its multiplication extends "by linearity" the given group law on the basis. Less formally, a group ring is a generalization of a given group, by attaching to each element of the group a "weighting factor" from a given ring. If the ring is commutative then the group ring is also referred to as a group algebra, for it is indeed an algebra over the given ring. A group algebra over a field has a further structure of a Hopf algebra; in this case, it is thus called a group Hopf algebra. The apparatus of group rings is especially useful in the theory of group representations. Definition Let ''G'' be a group, written multiplicatively, and let ''R'' be a ring. The group ring of '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Integral Monoid Ring
In abstract algebra, a monoid ring is a ring constructed from a ring and a monoid, just as a group ring is constructed from a ring and a group. Definition Let ''R'' be a ring and let ''G'' be a monoid. The monoid ring or monoid algebra of ''G'' over ''R'', denoted ''R'' 'G''or ''RG'', is the set of formal sums \sum_ r_g g, where r_g \in R for each g \in G and ''r''''g'' = 0 for all but finitely many ''g'', equipped with coefficient-wise addition, and the multiplication in which the elements of ''R'' commute with the elements of ''G''. More formally, ''R'' 'G''is the set of functions such that is finite, equipped with addition of functions, and with multiplication defined by : (\phi \psi)(g) = \sum_ \phi(k) \psi(\ell). If ''G'' is a group, then ''R'' 'G''is also called the group ring of ''G'' over ''R''. Universal property Given ''R'' and ''G'', there is a ring homomorphism sending each ''r'' to ''r''1 (where 1 is the identity element of ''G''), and a monoid homomorphism (wher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vector Bundle
In mathematics, a vector bundle is a topological construction that makes precise the idea of a family of vector spaces parameterized by another space X (for example X could be a topological space, a manifold, or an algebraic variety): to every point x of the space X we associate (or "attach") a vector space V(x) in such a way that these vector spaces fit together to form another space of the same kind as X (e.g. a topological space, manifold, or algebraic variety), which is then called a vector bundle over X. The simplest example is the case that the family of vector spaces is constant, i.e., there is a fixed vector space V such that V(x)=V for all x in X: in this case there is a copy of V for each x in X and these copies fit together to form the vector bundle X\times V over X. Such vector bundles are said to be ''trivial''. A more complicated (and prototypical) class of examples are the tangent bundles of smooth (or differentiable) manifolds: to every point of such a manifold w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colombeau Algebra
In mathematics, a Colombeau algebra is an algebra of a certain kind containing the space of Schwartz distributions. While in classical distribution theory a general multiplication of distributions is not possible, Colombeau algebras provide a rigorous framework for this. Such a multiplication of distributions has long been believed to be impossible because of L. Schwartz' impossibility result, which basically states that there cannot be a differential algebra containing the space of distributions and preserving the product of continuous functions. However, if one only wants to preserve the product of smooth functions instead such a construction becomes possible, as demonstrated first by Colombeau. As a mathematical tool, Colombeau algebras can be said to combine a treatment of singularities, differentiation and nonlinear operations in one framework, lifting the limitations of distribution theory. These algebras have found numerous applications in the fields of partial differential ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hilbert's Arithmetic Of Ends
In mathematics, specifically in the area of hyperbolic geometry, Hilbert's arithmetic of ends is a method for endowing a geometric set, the set of ideal points or "ends" of a hyperbolic plane, with an algebraic structure as a field. It was introduced by German mathematician David Hilbert. Definitions Ends In a hyperbolic plane, one can define an ''ideal point '' or ''end'' to be an equivalence class of limiting parallel rays. The set of ends can then be topologized in a natural way and forms a circle. This usage of ''end'' is not canonical; in particular the concept it indicates is different from that of a topological end (see End (topology) and End (graph theory)). In the Poincaré disk model or Klein model of hyperbolic geometry, every ray intersects the boundary circle (also called the ''circle at infinity'' or ''line at infinity'') in a unique point, and the ends may be identified with these points. However, the points of the boundary circle are not considered to be points ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hilbert Symbol
In mathematics, the Hilbert symbol or norm-residue symbol is a function (–, –) from ''K''× × ''K''× to the group of ''n''th roots of unity in a local field ''K'' such as the fields of reals or p-adic numbers . It is related to reciprocity laws, and can be defined in terms of the Artin symbol of local class field theory. The Hilbert symbol was introduced by in his Zahlbericht, with the slight difference that he defined it for elements of global fields rather than for the larger local fields. The Hilbert symbol has been generalized to higher local fields. Quadratic Hilbert symbol Over a local field ''K'' whose multiplicative group of non-zero elements is ''K''×, the quadratic Hilbert symbol is the function (–, –) from ''K''× × ''K''× to defined by :(a,b)=\begin+1,&\mboxz^2=ax^2+by^2\mbox(x,y,z)\in K^3;\\-1,&\mbox\end Equivalently, (a, b) = 1 if and only if b is equal to the norm of an element of the quadratic extension Ksqrt/math> page 110. Properties The follo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ward's Twistor Construction
Ward's is an American organization that has covered the automotive industry for over 80 years. The organization is responsible for several publications including, '' Ward's AutoWorld'', and '' Ward's Dealer Business''. Ward's also publish the annual list of Ward's 10 Best Engines. Ward's was acquired by International Thomson Publishing in 1981 and sold to K-III (later Primedia) in 1990. Prism Business Media acquired Ward's from Primedia in 2005; Penton merged with Prism in 2006. Penton was acquired by Informa in 2016. ''Ward's AutoWorld'' ''Ward's AutoWorld'' is an automobile trade magazine A trade magazine, also called a trade journal or trade paper (colloquially or disparagingly a trade rag), is a magazine or newspaper whose target audience is people who work in a particular trade or industry. The collective term for this .... It has been published since 1924, originally as ''Cram Report'', and continues into modern times with a monthly print version (''Ward ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
