0,1     0,1 These last two examples illustrate the fact that the boundary of a dense set with empty interior is its closure. In the space of rational numbers with the usual topology the subspace topology of R , the boundary of math infty, a math , where a is irrational, is empty. The boundary of a set is a topology topological notion and may change if one changes the topology. For example, given the usual topology on R sup 2 sup , the boundary of a closed disk   x , y     ... as its own topological space with the subspace topology of R sup 2 sup , then the boundary of the disk ...For a different notion of boundary related to manifold s, see that article. Image Runge theorem.svg right thumb A set in light blue and its boundary in dark blue . In topology and mathematics in general, the boundary of a subset S of a topological space X is the set of points which can be approached both from S and from the outside of S . More precisely, it is the set of points in the closure topology closure of S , not belonging to the interior topology interior of S . An element of the boundary of S is called a boundary point of S . Notations used for boundary of a set S include bd S , fr S , and S . Some authors for example Willard, in General Topology use the term frontier , instead of boundary in an attempt to avoid confusion with the concept of boundary used in algebraic topology and manifold theory . A Connected space Formal definition connected component of the boundary of S is called a boundary component of S . Common definitions There are several common and equivalent definitions to the boundary of a subset S of a topological space X the closure of S without the interior of S S   ... . the set of points p of X such that every neighborhood topology neighborhood of p contains at least ... right thumb Boundary of hyperbolic components of Mandelbrot set Consider the real line R with the usual topology i.e. the topology whose basis topology basis sets are open interval s . One has 0,5   ... more details
wiktionary Boundary plural boundaries may refer to any meaning below, also to border . Psychology main Psychology Personal boundaries Mathematics and Physics main Mathematics Physics Boundarytopology , the closure minus the interior of a subset of a topological space an edge in the topology of manifolds, as in the case of a manifold with boundaryBoundary value problem , a differential equation together with a set of additional restraints called the boundary conditions Boundary thermodynamic , the edge ... in landscape history , the divide between areas of differing land use Boundary real estate , the legal boundary between units of real property Boundary cricket , the edge of the playing field, or a scoring ... , a 2008 television series Boundary critique , a concept about the meaning and validity of propositions Communication privacy management theory Boundary Turbulence , a break in expectation of how private information is held within a group of knowledge owners Place names Boundary, Derbyshire , a civil parish and hamlet in South Derbyshire, England Boundary, Leicestershire , a village in Leicestershire, England Boundary, Staffordshire , a village in Staffordshire, England Boundary Ranges , also known as the Boundary Range, a mountain range in British Columbia, Canada and Alaska, United States Boundary Country , a region of southern British Columbia, Canada Kootenay Boundary Regional District , a regional district in British Columbia West Kootenay Boundary , a provincial electoral district in British Columbia Okanagan Boundary , a former provincial electoral district in British Columbia Boundary Similkameen , a former provincial electoral district in British Columbia Boundary Falls, British Columbia , also known as Boundary, a former railway town in the Boundary Country of British Columbia Stikine, British Columbia , called Boundary from 1930 to 1964, a former customs post on the Stikine River at the Alaska British Columbia border Ships MV Boundary , a number of ships with this name ... more details
one surface and one edge. Such shapes are an object of study in topology. Topology from the Greek ... or analysis situs Greek Latin for picking apart of place . This later acquired the modern name of topology Specify . By the middle of the 20th century, topology had become an important area of study within mathematics. The word topology is used both for the mathematical discipline and for a family ... object of topology. Of particular importance are homeomorphism s , which can be defined as continuous function s with a continuous inverse function inverse . Topology includes many subfields. The most basic and traditional division within topology is General topology point set topology , which establishes the foundational aspects of topology and investigates concepts inherent to topological spaces basic examples include compactness and connectedness algebraic topology , which generally tries ... mathematics homology and geometric topology , which primarily studies manifold s and their embeddings placements in other manifolds. Some of the most active areas, such as low dimensional topology and graph ... , the simplest non trivial knot See also topology glossary for definitions of some of the terms used in topology and topological space for a more technical treatment of the subject. History Image Konigsberg .... Topology began with the investigation of certain questions in geometry. Leonhard Euler s 1736 ... academic treatises in modern topology. The term Topologie was introduced in German in 1847 by Johann ... years in correspondence before its first appearance in print. Topology, its English form, was first ... topologist in the sense of a specialist in topology was used in 1905 in the magazine The Spectator ... definition of topology. Modern topology depends strongly on the ideas of set theory , developed ... of homotopy and homology mathematics homology , which are now considered part of algebraic topology ..., see point set topology and algebraic topology . Elementary introduction Topology, as a branch ... more details
for the mathematical journal Geometry & Topology In mathematics , geometry and topology is an umbrella term for geometry and topology , as the line between these two is often blurred, most visibly in Riemannian ... like the Gauss Bonnet theorem and Chern Weil theory . Sharp distinctions between geometry and topology can be drawn, however, as discussed below. It is also the title of a journal Geometry & Topology that covers these topics. Scope It is distinct from geometric topology , which more narrowly involves applications of topology to geometry. It includes Differential geometry and topology Geometric topology including low dimensional topology and surgery theory It does not include such parts of algebraic topology as homotopy theory , but some areas of geometry and topology such as surgery theory, particularly algebraic surgery theory are heavily algebraic. Distinction between geometry and topology Pithily, geometry has local structure or infinitesimal , while topology only has global structure. Alternatively, geometry has continuous moduli, while topology has discrete moduli. By examples, an example of geometry is Riemannian geometry , while an example of topology is homotopy theory . The study of metric space s is geometry, the study of topological space s is topology. The terms are not used completely consistently symplectic manifold s are a boundary case, and coarse geometry is global ... beyond dimension . So differentiable structures on a manifold is an example of topology. By contrast ... structure is topology. If have non trivial deformations, the structure is said to be flexible , and its ... so studying maps up to homotopy is topology. Similarly, differentiable structures on a manifold is usually a discrete space, and hence an example of topology, but exotic R4 exotic R sup 4 sup s have .... Symplectic manifolds Symplectic manifold s are a boundary case, and parts of their study are called symplectic topology and symplectic geometry . By Darboux s theorem , a symplectic manifold has no local ... more details
The notion of a fork appears in the characterization of graph mathematics graph s, including network topology , and topological space s. image 6n graf.svg thumb A graph with forks in vertices 2, 4, and 5. A graph has a fork in any vertex graph theory vertex which is connected by three or more graph theory edges . Correspondingly, a topological space is said to have a fork if it has a subset which is homeomorphic to the Glossary of graph theory Graph topology graph topology of a graph with a fork. Stated in terms of topology alone, a topological space X has a fork if X has a Closed set closed subset T with connected space connected Interior topology interior , whose Boundary topology boundary consists of three distinct elements and for which the boundary of the complement set theory complement of T s interior relative to X consists of these same three elements. It is perhaps worth noting that certain definitions of a Curve Simple curve simple curve as Map mathematics map c I X of a Real number real valued Interval mathematics interval I to a topological space X such that c is continuous function topology continuous and injective with the exception, for closed curves, of the two interval endpoints are Strength mathematics weaker than the requirement that its range X be a connected topological space without forks. topology stub Category Topological graph theory ... more details
incomplete date August 2009 In mathematics , general topology or point set topology is the branch of topology ... from other branches of topology in that the topological spaces may be very general, and do not have to be at all similar to manifold s. General topology provides the most general framework where fundamental concepts of topology such as open closed sets, continuity, interior exterior boundary points, and limit points could be defined. Definition Main Topological Space A topology is a pair X , .... History General topology grew out of a number of areas, most importantly the following the detailed study of subsets of the real line once known as the topology of point sets , this usage is now obsolete ... s, in the early days of functional analysis . General topology assumed its present form around 1940 ..., it is in general topology that basic notions are defined and theorems about them proved. This includes the following open set open and closed set s interior topology interior and closure topology closure neighbourhood topology neighbourhood and closeness topology closeness compact space compactness and connected space connectedness continuous function topology continuous function mathematics ... branches of mathematics. Set theoretic topology examines such questions when they have substantial relations to set theory , as is often the case. Other main branches of topology are algebraic topology , geometric topology , and differential topology . As the name implies, general topology provides the common foundation for these areas. An important variant of general topology is pointless topology , which, rather than using sets of points as its foundation, builds up topological concepts ... and locales . See also List of examples in general topology Glossary of general topology for detailed definitions List of general topology topics for related articles Category of topological spaces References Some standard books on general topology include Bourbaki cite Topologie G n rale cite ... more details
In mathematics , a strong topology is a topology which is stronger than some other default topology. This term is used to describe different topologies depending on context, and it may refer to the final topology on the disjoint union topology disjoint union the topology arising from a normed vector space norm the strong operator topology the strong topology polar topology , which subsumes all topologies above. Note that a topology is stronger than a topology is a Comparison of topologies finer topology if contains all the open sets of . In algebraic geometry , it usually means the topology of an algebraic variety as complex manifold or subspace of complex projective space , as opposed to the Zariski topology which is rarely even a Hausdorff space . See also Weak topology mathdab Category Topology ... more details
In functional analysis and related areas of mathematics the strong topology is the finer topology finest polar topology , the topology with the most open set s, on a dual pair . The coarser topology coarsest polar topology is called weak topology polar topology weak topology . Definition Given a dual pair math X,Y, langle , rangle math the strong topology math beta Y, X math on math Y math is the polar topology defined by using the family of all sets in math X math where the polar set in math Y math is Absorption law absorbent . Examples Given a normed vector space math X math and its continuous dual math X math then math beta X , X math topology on math X math is identical to the topology induced by the operator norm . Conversely math beta X, X math topology on math X math is identical to the topology induced by the norm mathematics norm . Properties In barrelled space s the strong topology is identical to the Mackey topology . mathanalysis stub Category Topology of function spaces ... more details
Digital topology deals with properties and features of two dimensional 2D or Three dimensional space three dimensional 3D digital images that correspond to topological properties e.g., connectedness or topological features e.g., Boundarytopology boundaries of objects. Concepts and results of digital topology are used to specify and justify important low level image analysis algorithms, including algorithms for thinning, border or surface tracing, counting of components or tunnels, or region filling. History Digital topology was first studied in the late 1960s by the computer image analysis researcher ... and developing the field. The term digital topology was itself invented by Rosenfeld, who used it in a 1973 publication for the first time. A related work called the grid cell topology appeared ... topology . Rosenfeld et al. proposed digital connectivity such as 4 connectivity and 8 connectivity ... grid cell topology to 3D and high dimensions. He also proposed 2008 a more general axiomatic theory ... . It is the Alexandrov topology. The book of 2008 contains new definitions of topological balls ... and computer vision. Basic results A basic early result in digital topology says that 2D binary ... use corresponds to open or closed sets in the 2D grid cell topology , and the result generalizes ... topology . Grid cell topology also applies to multilevel e.g., color 2D or 3D images, for example ... and Rosenfeld, 2004 . Digital topology is highly related to combinatorial topology . The main differences between them are 1 digital topology mainly studies digital objects that are formed by grid cells, clarify reason How does that differ? date October 2011 and 2 digital topology also deals with non ... topology Computational geometry Computational topology Topological data analysis Topology Discrete ... of Digital Discrete Geometry and Topology publisher SP Computing year 2004 isbn 0 9755122 1 8 cite book ... Category Digital topology fa ... more details
In mathematics , the uniform topology on a space has several different meanings depending on the context In functional analysis, it sometimes refers to a polar topology on a topological vector space. In general topology, it is the topology carried by a uniform space . In real analysis, it is the topology of uniform convergence . Disambig ... more details
In mathematics, fine topology can refer to Fine topology potential theory The sense opposite to coarse topology , namely A term in comparison of topologies which specifies the partial order relation of a topological structure to other one s Final topology See also Discrete topology , the most fine topology possible on a given set mathdab ... more details
Wikify date October 2010 Topology optimisation is a mathematical approach that optimises material layout within a given design space, for a given set of loads and boundary conditions such that the resulting layout meets a prescribed set of performance targets. Using topology optimisation, engineers can find the best concept design that meets the design requirements. Topology optimisation has been implemented .... ref and topological derivative s. Topology optimisation is used at the concept level of the design ... from a topology optimisation, although optimal, may be expensive or infeasible to manufacture. These challenges can be overcome through the use of manufacturing constraints in the topology optimisation ... from meshing of the domain. Topology Optimization for Stiff Structures A stiff structure is one that has the least possible displacement when given certain set of boundary conditions. A global measure ... boundary conditions. The lower the strain energy the higher the stiffness of the structure. So ... , A reference that proved the validity of the interpolation scheme. ref So one could view topology ... in Topology Optimization.tif thumb Checker Board Patterns are shown in this result. Some ... of these issues. File Topology Optimization with filtereing.tif thumb Topology Optimization result when filtering is used blockquote Distinction Topology optimization is distinct from shape optimization ... topological properties, such as having a fixed number of holes in them. Therefore topology optimisation is used to generate concepts and shape optimisation is used to fine tune a chosen design topology. There are various methods used to perform topology optimisation Solid Isotropic Material with Penalisation ... Investigation into Structural Topology Optimization Problem Formulations, William Renold, lulu.com ... Implementation of Topology Optimization Uwe Schramm, Ming Zhou IUTAM Symposium on Topological Design ... Implementation and Applications of Topology Optimization and Future Needs Claus B.W. Pedersen Peter ... more details
In mathematics, coarse topology is a term in comparison of topologies which specifies the partial order relation of a topological structure to other one s . Specifically, it may refer to Initial topology , the most coarse topology in a certain category of topologies Trivial topology , the most coarse topology possible on a given set See also Weak topology , an example of topology coarser than the standard one Fine topology disambiguation mathdab ... more details
Unreferenced date December 2009 In mathematics , a closed n manifold N embedding embedded in an n 1 manifold M is boundary parallel or parallel , or peripheral if there is an isotopy of N onto a Boundary topology boundary connected space component of M . An example Consider the Annulus mathematics annulus math I times S 1 math . Let denote the projection map math pi I times S 1 rightarrow S 1, qquad x,z mapsto z. math If a circle S is embedded into the annulus so that Restriction Restrictions and extensions restricted to S is a bijection , then S is boundary parallel. The Converse logic converse is not true. If, on the other hand, a circle S is embedded into the annulus so that restricted to S is not Surjection surjective , then S is not boundary parallel. Again, the converse is not true. Image Annulus.circle.pi 1 injective.png thumb left An example wherein &pi is not bijective on S , but S is &part parallel anyway. Image Annulus.circle.bijective projection.png thumb left An example wherein &pi is bijective on S . Image Annulus.circle.nulhomotopic.png thumb left An example wherein &pi is not surjective on S . Clear DEFAULTSORT Boundary Parallel Category Geometric topology ... more details
. BoundarytopologyBoundary The boundarytopologyboundary or frontier of a set is the set s closure minus its interior. Equivalently, the boundary of a set is the intersection of its closure with the closure of its complement. Boundary of a set math A math is denoted by math partial A math or math ... T sub 1 sub . Frontier See BoundarytopologyBoundary . Full set A compact space compact subset K of the complex ... as topology . Although there is no absolute distinction between different areas of topology, the focus here is on general topology . The following definitions are also fundamental to algebraic topology , differential topology and geometric topology . See the article on topological space s for basic definitions and examples, and see the article on topology for a brief history and description of the subject ... contain specialised vocabulary within general topology or provide more detailed expositions of the definitions given below. The list of general topology topics and the list of examples in general topology will also be very helpful. Compact space Connected space Continuity topology Continuity Metric ... yes A Accessible See T1 space math T 1 math . Accumulation point See limit point . Alexandrov topology A space X has the Alexandrov topology or is finitely generated if arbitrary intersections of open ... the natural numbers to the natural numbers, with the topology of pointwise convergence see Baire space set theory . Base topology Base A collection B of open sets is a base topology base or basis for a topology math tau math if every open set in math tau math is a union of sets in math B math . The topology math tau math is the smallest topology on math X math containing math B math and is said to be generated by math B math . Basis topology Basis See Base topology Base . Borel algebra The Borel ... set in the topology induced on M by d . Note that the closed ball D x r might not be equal to the closure topology closure of the open ball B x r . Closed set A set is Closed set closed if its ... more details
In mathematics , a shelling of a simplicial complex is a way of gluing it together from its maximal simplices in a well behaved way. A complex admitting a shelling is called shellable . Definition A d dimensional simplicial complex is called pure if its maximal simplices all have dimension d . Let math Delta math be a finite or countably infinite simplicial complex. An ordering math C 1,C 2, ldots math of the maximal simplices of math Delta math is a shelling if the complex math B k left bigcup i 1 k 1 C i right cap C k math is pure and math dim C k 1 math dimensional for all math k 2,3, ldots math . If math B k math is the entire boundary of math C k math then math C k math is called spanning . For math Delta math not necessarily countable, one can define a shelling as a well ordering of the maximal simplices of math Delta math having analogous properties. Properties A shellable complex is homotopy homotopy equivalent to a wedge sum of n sphere spheres , one for each spanning simplex and of corresponding dimension. A shellable complex may admit many different shellings, but the number of spanning simplices, and their dimensions, do not depend on the choice of shelling. This follows from the previous property. Examples Every Coxeter complex , and more generally every building mathematics building , is shellable. ref Cite journal issn 0001 8708 volume 52 issue 3 pages 173 212 last Bj rner first Anders title Some combinatorial and algebraic properties of Coxeter complexes and Tits buildings journal Advances in Mathematics date 1984 06 doi 10.1016 0001 8708 84 90021 5 ref References cite book author Dmitry Kozlov title Combinatorial Algebraic Topology publisher Springer location Berlin year 2008 isbn 978 3 540 71961 8 oclc doi reflist Category Topology Category Algebraic topology topology stub ... more details
Unreferenced date December 2009 In functional analysis , a branch of mathematics , the ultraweak topology , also called the weak topology , or weak operator topology or weak topology , on the set B H of bounded operator s on a Hilbert space is the weak topology weak topology obtained from the predual B sub sub H of B H , the trace class operators on H . In other words it is the weakest topology such that all elements of the predual are continuous when considered as functions on B H . Relation with the weak operator topology The ultraweak topology is similar to the weak operator topology. For example, on any norm bounded set the weak operator and ultraweak topologies are the same, and in particular the unit ball is compact in both topologies. The ultraweak topology is stronger than the weak operator topology. One problem with the weak operator topology is that the dual of B H with the weak operator topology is too small . The ultraweak topology fixes this problem the dual is the full predual B sub sub H of all trace class operators. In general the ultraweak topology is more useful than the weak operator topology, but it is more complicated to define, and the weak operator topology is often more apparently convenient. The ultraweak topology can be obtained from the weak operator topology as follows. If H sub 1 sub is a separable infinite dimensional Hilbert space then B H can be embedded in B H H sub 1 sub by tensoring with the identity map on H sub 1 sub . Then the restriction of the weak operator topology on B H H sub 1 sub is the ultraweak topology of B H . See also Topologies on the set of operators on a Hilbert space ultrastrong topology weak operator topology DEFAULTSORT Ultraweak Topology Category Topology of function spaces Category Von Neumann algebras ... more details
. For more on this matter, see Interior topology Interior operator interior operator below. Examples ... R math has the lower limit topology , then int 0, 1 nowiki 0, 1 nowiki . If one considers on math mathbb R math the topology in which every set is open, then int 0, 1 0, 1 . If one considers on math mathbb R math the topology in which the only open sets are the empty set and math mathbb R math itself, then int 0, 1 is the empty set. These examples show that the interior of a set depends upon the topology ... operator sup o sup is dual to the Closure topology closure operator sup sup , in the sense ... of a set main Exterior topology The exterior of a subset S of a topological space X , denoted ext ... topology Category Closure operators ar cs Vnit ek mno iny da Indre matematik de Innerer ... more details
Unreferenced date December 2009 In functional analysis and related areas of mathematics the weak topology is the coarser topology coarsest polar topology , the topology with the fewest open set s, on a dual pair . The finer topology finest polar topology is called strong topology polar topology strong topology . Under the weak topology the Bounded set topological vector space bounded set s coincide with the relatively compact set s which leads to the important Bourbaki Alaoglu theorem . Definition Given a dual pair math X,Y, langle , rangle math the weak topology math sigma X,Y math is the weakest polar topology on math X math so that math X, sigma X,Y simeq Y math . That is the continuous dual of math X, sigma X,Y math is equal to math Y math up to isomorphism . The weak topology is constructed as follows For every math y math in math Y math on math X math we define a semi norm on math X math math p y X to mathbb R math with math p y x vert langle x , y rangle vert qquad x in X math This family of semi norms defines a locally convex topology on math X math . Examples Given a normed vector space math X math and its continuous dual math X math , math sigma X, X math is called the weak topology on math X math and math sigma X , X math the weak star topology weak topology on math X math DEFAULTSORT Weak Topology Polar Topology Category Topology of function spaces ... more details
Logical topology also referred to as signal topology is a network computing term used to describe the arrangement of devices on a network and how they communicate with one another. How devices are connected to the network through the actual cables that transmit data, or the physical structure of the network, is called the Network topology physical topology . Logical topologies are bound to network protocols and describe how data is moved across the network. There are attempts to study the logical topology of the Internet by network scientists such as Albert L szl Barab si . Category Network topology ar ... more details
Unreferenced date December 2009 In functional analysis and related areas of mathematics a dual topology is a locally convex topology on a dual pair , two vector space s with a bilinear form defined on them, so that one vector space becomes the continuous dual of the other space. The different dual topologies for a given dual pair are characterized by the Mackey Arens theorem. All locally convex topologies with their continuous dual are trivially a dual pair and the locally convex topology is a dual topology. Several topological properties depend only on the dual pair and not on the chosen dual topology and thus it is often possible to substitute a complicated dual topology by a simpler one. Definition Given a dual pair math X, Y, langle , rangle math , a dual topology on math X math is a locally convex topology math tau math so that math X, tau simeq Y. math That is the continuous dual of math X, tau math is equal to math Y math up to linear isomorphism . Properties Theorem by George Mackey Mackey Given a dual pair, the bounded set topological vector space bounded set s under any dual topology are identical. Under any dual topology the same sets are barrelled set barrelled . Characterization of dual topologies The Mackey Arens theorem , named after George Mackey and Richard Friedrich Arens Richard Arens , characterizes all possible dual topologies on a locally convex space s. The theorem shows that the coarser topology coarsest dual topology is the weak topology , the topology of uniform convergence on all finite subsets of math X math , and the finer topology finest topology is the Mackey topology , the topology of uniform convergence on all weakly compact subsets of math ... and math X math its continuous dual then math tau math is a dual topology on math X math if and only if it is a topology of uniform convergence on a family of absolutely convex and weak topology weakly compact subsets of math X math DEFAULTSORT Dual Topology Category Topology of function spaces ... more details
unreferenced date May 2011 In any domain of mathematics , a space has a natural topology if there is a topology on the space which is best adapted to its study within the domain in question. In many cases this imprecise definition means little more than the assertion that the topology in question arises naturally or canonically see mathematical jargon in the given context. Note that in some cases multiple ... X , then the Order topology Induced order topology induced order topology , i.e. the order topology of the totally ordered Y , where this order is inherited from X , is coarser than the subspace topology of the order topology of X . Natural topology does quite often have a more specific meaning, at least given some prior contextual information the natural topology is a topology which makes a natural map or collection of maps Continuous function topology continuous . This is still imprecise, even ... property. However, there is often a finest topology finest or coarsest topology coarsest topology ... topology. The simplest cases which nevertheless cover many examples are the initial topology and the final topology Willard 1970 . The initial topology is the coarsest topology on a space X which makes a given collection of maps from X to topological spaces X sub i sub continuous. The final topology is the finest topology on a space X which makes a given collection of maps from topological spaces ... and quotient spaces. The natural topology on a subset of a topological space is the subspace topology . This is the coarsest topology which makes the inclusion map continuous. The natural topology on a quotient space quotient of a topological space is the quotient topology . This is the finest topology which makes the quotient map continuous. Other examples include the topology induced by the Helly metric . References cite book last Willard first Stephen title General Topology publisher Addison ... Mathematical structures Category Topologytopology stub ... more details
deformation retracts onto a rose with 2 g petals, namely the boundary of a fundamental polygon . A rose ... Allen author link Allen Hatcher title Algebraic topology url http www.math.cornell.edu hatcher AT ATchapters.html ... 79540 0 oclc doi citation last Munkres first James R. author link James Munkres title Topology publisher ... citation last Stillwell first John author link title Classical topology and combinatorial group theory ... spaces Category Algebraic topology ja pt Bouquet de c rculos ... more details
Infobox Book name Counterexamples in Topology image image caption author Lynn Steen Lynn Arthur Steen ... Counterexamples in Topology 1970, 2nd ed. 1978 is a book on mathematics by topology topologist s Lynn ... a counterexample which exhibits one property but not the other. In Counterexamples in Topology , Steen ... , Minnesota in the summer of 1967, canvassed the field of topology for such counterexamples and compiled ... space which is not second countable space second countable is counterexample 3, the discrete topology ... of metrization theory and general topology see History of the separation axioms for more. List of mentioned counterexamples colbegin cols 2 finite set Finite discrete topology Countable discrete topology Uncountable discrete topology Indiscrete topology Partition topology Odd even topology Deleted integer topology Particular point topology Finite particular point topology Particular point topology Countable particular point topology Particular point topology Uncountable particular point topology Sierpinski space , see also particular point topology Closed extension topology Finite excluded point topology Countable excluded point topology Uncountable excluded point topology Open extension topology Either or topology Finite complement topology on a countable space Finite complement topology on an uncountable space Countable complement topology Double pointed countable complement topology Compact complement topology Countable Fort space Uncountable Fort space Fortissimo space Arens Fort space Modified Fort space Euclidean space Euclidean topology Cantor set Rational number s Irrational ... topology One point compactification of the rationals Hilbert space Fr chet space Hilbert cube Order topology Open ordinal space 0, where Closed ordinal space 0, where Open ordinal space 0, Closed ordinal space 0, Uncountable discrete ordinal space Long line topology Long line Long line topology Extended long line An altered Long line topology long line Lexicographic order topology ... more details
String topology , a branch of mathematics , is the study of algebraic structures on the homology theory homology of free loop space s. The field was started by Chas and Sullivan in 1999 see Chas & Sullivan 1999 . Motivation While the singular cohomology of a space has always a product structure, this is not true for the singular homology of a space. Nevertheless, it is possible to construct such a structure for an oriented manifold M of dimension d. This is the so called intersection product . Intuitively, one can describe it as follows given classes math x in H p M math and math y in H q M math , take their product math x times y in H p q M times M math and make it transversal to the diagonal math M hookrightarrow M times M math . The intersection is then a class in math H p q d M math , the intersection ... attempts to construct topological field theories via string topology. The basic idea is to fix an oriented manifold M and associate to every surface with p incoming and q outgoing boundary components ... boundary. Ignoring the open closed part, this amounts to the following structure let S be a surface with boundary, where the boundary circles are labeled as incoming or outcoming. If there are p ... & D. Sullivan, String Topology , http arxiv.org abs math 9911159 arXiv math 9911159v1 1999 R. Cohen & J. Jones, A homotopy theoretic realization of string topology , Mathematische Annalen 324, p. 773 ... in Categorical decomposition techniques in algebraic topology International Conference in Algebraic Topology, Isle of Skye, Scotland, June 2001 , Birkh user, p. 77&ndash 92 2004 . L. Meier, Spectral Sequences in String Topology , http arxiv.org abs 1001.4906 arXiv 1001.4906v2 2010 V. Godin, Higher string topology operations , http arXiv.org abs 0711.4859 arXiv 0711.4859v2 2008 H. Tamanoi, Loop coproducts in string topology and triviality of higher genus TQFT operations , Journal of Pure and Applied Algebra 214, Issue 5 pp. 605 615 2010 Category Geometric topology Category Algebraic topology ... more details