Integral Map

	Integral Map In mathematical analysis, an integral linear operator is a linear operator ''T'' given by integration; i.e., :(Tf)(x) = \int f(y) K(x, y) \, dy where K(x, y) is called an integration kernel. More generally, an integral bilinear form is a bilinear functional that belongs to the continuous dual space of X \widehat_ Y, the injective tensor product of the locally convex topological vector spaces (TVSs) ''X'' and ''Y''. An integral linear operator is a continuous linear operator that arises in a canonical way from an integral bilinear form. These maps play an important role in the theory of nuclear spaces and nuclear maps. Definition - Integral forms as the dual of the injective tensor product Let ''X'' and ''Y'' be locally convex TVSs, let X \otimes_ Y denote the projective tensor product, X \widehat_ Y denote its completion, let X \otimes_ Y denote the injective tensor product, and X \widehat_ Y denote its completion. Suppose that \operatorname : X \otimes_ Y \to X \wideha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Bilinear Map In mathematics, a bilinear map is a function combining elements of two vector spaces to yield an element of a third vector space, and is linear in each of its arguments. Matrix multiplication is an example. A bilinear map can also be defined for modules. For that, see the article pairing. Definition Vector spaces Let V, W and X be three vector spaces over the same base field F. A bilinear map is a function B : V \times W \to X such that for all w \in W, the map B_w v \mapsto B(v, w) is a linear map from V to X, and for all v \in V, the map B_v w \mapsto B(v, w) is a linear map from W to X. In other words, when we hold the first entry of the bilinear map fixed while letting the second entry vary, the result is a linear operator, and similarly for when we hold the second entry fixed. Such a map B satisfies the following properties. * For any \lambda \in F, B(\lambda v,w) = B(v, \lambda w) = \lambda B(v, w). * The map B is additive in both components: if v_1, v_2 \in V an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Complete Metric Space In mathematical analysis, a metric space is called complete (or a Cauchy space) if every Cauchy sequence of points in has a limit that is also in . Intuitively, a space is complete if there are no "points missing" from it (inside or at the boundary). For instance, the set of rational numbers is not complete, because e.g. \sqrt is "missing" from it, even though one can construct a Cauchy sequence of rational numbers that converges to it (see further examples below). It is always possible to "fill all the holes", leading to the ''completion'' of a given space, as explained below. Definition Cauchy sequence A sequence x_1, x_2, x_3, \ldots of elements from X of a metric space (X, d) is called Cauchy if for every positive real number r > 0 there is a positive integer N such that for all positive integers m, n > N, d(x_m, x_n) < r. Complete space A metric space $(X, d)$ is complete if any of the following equivalent conditions are satisfied: #Every Cauchy seq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Topological Vector Spaces In mathematics, a topological vector space (also called a linear topological space and commonly abbreviated TVS or t.v.s.) is one of the basic structures investigated in functional analysis. A topological vector space is a vector space that is also a topological space with the property that the vector space operations (vector addition and scalar multiplication) are also continuous functions. Such a topology is called a and every topological vector space has a uniform topological structure, allowing a notion of uniform convergence and completeness. Some authors also require that the space is a Hausdorff space (although this article does not). One of the most widely studied categories of TVSs are locally convex topological vector spaces. This article focuses on TVSs that are not necessarily locally convex. Other well-known examples of TVSs include Banach spaces, Hilbert spaces and Sobolev spaces. Many topological vector spaces are spaces of functions, or linear operators actin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Topological Tensor Product In mathematics, there are usually many different ways to construct a topological tensor product of two topological vector spaces. For Hilbert spaces or nuclear spaces there is a simple well-behaved theory of tensor products (see Tensor product of Hilbert spaces), but for general Banach spaces or locally convex topological vector spaces the theory is notoriously subtle. Motivation One of the original motivations for topological tensor products \hat is the fact that tensor products of the spaces of smooth real-valued functions on \R^n do not behave as expected. There is an injection :C^\infty(\R^n) \otimes C^\infty(\R^m) \hookrightarrow C^\infty(\R^) but this is not an isomorphism. For example, the function f(x,y) = e^ cannot be expressed as a finite linear combination of smooth functions in C^\infty(\R_x)\otimes C^\infty(\R_y). We only get an isomorphism after constructing the topological tensor product; i.e., :C^\infty(\R^n) \mathop C^\infty(\R^m) \cong C^\infty(\R^). This a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Projective Tensor Product In functional analysis, an area of mathematics, the projective tensor product of two locally convex topological vector spaces is a natural topological vector space structure on their tensor product. Namely, given locally convex topological vector spaces X and Y, the projective topology, or π-topology, on X \otimes Y is the strongest topology which makes X \otimes Y a locally convex topological vector space such that the canonical map (x,y) \mapsto x \otimes y (from X\times Y to X \otimes Y) is continuous. When equipped with this topology, X \otimes Y is denoted X \otimes_\pi Y and called the projective tensor product of X and Y. It is a particular instance of a topological tensor product. Definitions Let X and Y be locally convex topological vector spaces. Their projective tensor product X \otimes_\pi Y is the unique locally convex topological vector space with underlying vector space X \otimes Y having the following universal property: :For any locally convex topological vect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Nuclear Space In mathematics, nuclear spaces are topological vector spaces that can be viewed as a generalization of finite-dimensional Euclidean spaces and share many of their desirable properties. Nuclear spaces are however quite different from Hilbert spaces, another generalization of finite-dimensional Euclidean spaces. They were introduced by Alexander Grothendieck. The topology on nuclear spaces can be defined by a family of seminorms whose unit balls decrease rapidly in size. Vector spaces whose elements are "smooth" in some sense tend to be nuclear spaces; a typical example of a nuclear space is the set of smooth functions on a compact manifold. All finite-dimensional vector spaces are nuclear. There are no Banach spaces that are nuclear, except for the finite-dimensional ones. In practice a sort of converse to this is often true: if a "naturally occurring" topological vector space is a Banach space, then there is a good chance that it is nuclear. Original motivation: The Schwartz ker ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Nuclear Operator In mathematics, nuclear operators are an important class of linear operators introduced by Alexander Grothendieck in his doctoral dissertation. Nuclear operators are intimately tied to the projective tensor product of two topological vector spaces (TVSs). Preliminaries and notation Throughout let ''X'',''Y'', and ''Z'' be topological vector spaces (TVSs) and ''L'' : ''X'' → ''Y'' be a linear operator (no assumption of continuity is made unless otherwise stated). * The projective tensor product of two locally convex TVSs ''X'' and ''Y'' is denoted by X \otimes_ Y and the completion of this space will be denoted by X \widehat_ Y. * ''L'' : ''X'' → ''Y'' is a topological homomorphism or homomorphism, if it is linear, continuous, and L : X \to \operatorname L is an open map, where \operatorname L, the image of ''L'', has the subspace topology induced by ''Y''. If ''S'' is a subspace of ''X'' then both the quotient map ''X'' → ''X''/''S'' and the canonical injection ''S' ... [...More Info...] [...Related Items...] OR:** [Wikipedia] [Google] [Baidu]
	Injective Tensor Product In mathematics, an injective function (also known as injection, or one-to-one function ) is a function that maps distinct elements of its domain to distinct elements of its codomain; that is, implies (equivalently by contraposition, implies ). In other words, every element of the function's codomain is the image of one element of its domain. The term must not be confused with that refers to bijective functions, which are functions such that each element in the codomain is an image of exactly one element in the domain. A homomorphism between algebraic structures is a function that is compatible with the operations of the structures. For all common algebraic structures, and, in particular for vector spaces, an is also called a . However, in the more general context of category theory, the definition of a monomorphism differs from that of an injective homomorphism. This is thus a theorem that they are equivalent for algebraic structures; see for more details. A functio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Final Topology In general topology and related areas of mathematics, the final topology (or coinduced, weak, colimit, or inductive topology) on a Set (mathematics), set X, with respect to a family of functions from Topological space, topological spaces into X, is the finest topology on X that makes all those functions Continuous function (topology), continuous. The Quotient space (topology), quotient topology on a quotient space is a final topology, with respect to a single surjective function, namely the quotient map. The Disjoint union (topology), disjoint union topology is the final topology with respect to the inclusion maps. The final topology is also the topology that every direct limit in the category of topological spaces is endowed with, and it is in the context of direct limits that the final topology often appears. A topology is Coherent topology, coherent with some collection of Subspace topology, subspaces if and only if it is the final topology induced by the natural inclusions. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Auxiliary Normed Spaces In functional analysis, a branch of mathematics, two methods of constructing normed spaces from disks were systematically employed by Alexander Grothendieck to define nuclear operators and nuclear spaces. One method is used if the disk D is bounded: in this case, the auxiliary normed space is \operatorname D with norm p_D(x) := \inf_ r. The other method is used if the disk D is absorbing: in this case, the auxiliary normed space is the quotient space X / p_D^(0). If the disk is both bounded and absorbing then the two auxiliary normed spaces are canonically isomorphic (as topological vector spaces and as normed spaces). Induced by a bounded disk – Banach disks Throughout this article, X will be a real or complex vector space (not necessarily a TVS, yet) and D will be a disk in X. Seminormed space induced by a disk Let X will be a real or complex vector space. For any subset D of X, the ''Minkowski functional'' of D defined by: If D = \varnothing then define p_(x) : \ \t ... [...More Info...] [...Related Items...] OR:* [Wikipedia] [Google] [Baidu]
	Fréchet Space In functional analysis and related areas of mathematics, Fréchet spaces, named after Maurice Fréchet, are special topological vector spaces. They are generalizations of Banach spaces ( normed vector spaces that are complete with respect to the metric induced by the norm). All Banach and Hilbert spaces are Fréchet spaces. Spaces of infinitely differentiable functions are typical examples of Fréchet spaces, many of which are typically Banach spaces. A Fréchet space X is defined to be a locally convex metrizable topological vector space (TVS) that is complete as a TVS, meaning that every Cauchy sequence in X converges to some point in X (see footnote for more details).Here "Cauchy" means Cauchy with respect to the canonical uniformity that every TVS possess. That is, a sequence x_ = \left(x_m\right)_^ in a TVS X is Cauchy if and only if for all neighborhoods U of the origin in X, x_m - x_n \in U whenever m and n are sufficiently large. Note that this definiti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	TVS-embedding In mathematics, a topological vector space (also called a linear topological space and commonly abbreviated TVS or t.v.s.) is one of the basic structures investigated in functional analysis. A topological vector space is a vector space that is also a topological space with the property that the vector space operations (vector addition and scalar multiplication) are also continuous functions. Such a topology is called a and every topological vector space has a uniform topological structure, allowing a notion of uniform convergence and completeness. Some authors also require that the space is a Hausdorff space (although this article does not). One of the most widely studied categories of TVSs are locally convex topological vector spaces. This article focuses on TVSs that are not necessarily locally convex. Other well-known examples of TVSs include Banach spaces, Hilbert spaces and Sobolev spaces. Many topological vector spaces are spaces of functions, or linear operators acting on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]