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John Milnor
John Willard Milnor (born February 20, 1931) is an American mathematician known for his work in differential topology, algebraic K-theory and low-dimensional holomorphic dynamical systems. Milnor is a distinguished professor at Stony Brook University and the only mathematician to have won the Fields Medal, the Wolf Prize, the Abel Prize and all three Steele prizes. Early life and career Milnor was born on February 20, 1931, in Orange, New Jersey. His father was J. Willard Milnor, an engineer, and his mother was Emily Cox Milnor. As an undergraduate at Princeton University he was named a Putnam Fellow in 1949 and 1950 and also proved the Fáry–Milnor theorem when he was only 19 years old. Milnor graduated with an A.B. in mathematics in 1951 after completing a senior thesis, titled "Link groups", under the supervision of Ralph Fox. He remained at Princeton to pursue graduate studies and received his Ph.D. in mathematics in 1954 after completing a doctoral dissertation, t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beno Eckmann
Beno Eckmann (31 March 1917 – 25 November 2008) was a Switzerland, Swiss mathematician who made contributions to algebraic topology, homological algebra, group theory, and differential geometry. Life Born to a Jewish family in Bern, Eckmann received his master's degree from ETH Zurich, Eidgenössische Technische Hochschule Zürich (ETH) in 1939. Later, he studied there under Heinz Hopf, obtaining his Ph.D. in 1941. His dissertation, on homotopy theory, was jointly supervised by Heinz Hopf and Ferdinand Gonseth. In 1942 he obtained a lecturer position at the University of Lausanne. He became an extraordinary professor there before, in 1948, taking a full professorship at ETH Zurich, where he remained until his 1984 retirement. He was also President of the Swiss Mathematical Society for 1961–1962, and the founding head of the Mathematics Research Institute at ETH Zurich from 1964 until his retirement. Recognition A colloquium in honor of Eckmann's 60th birthday was held in Zu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Microbundle
In mathematics, a microbundle is a generalization of the concept of vector bundle, introduced by the American mathematician John Milnor in 1964. It allows the creation of bundle-like objects in situations where they would not ordinarily be thought to exist. For example, the tangent bundle is defined for a smooth manifold but not a topological manifold; use of microbundles allows the definition of a ''topological'' tangent bundle. Definition A (topological) ''n''-microbundle over a topological space ''B'' (the "base space") consists of a triple (E, i, p), where ''E'' is a topological space (the "total space"), ''i: B \to E'' and ''p: E \to B'' are continuous maps (respectively, the "zero section" and the "projection map") such that: #the composition ''p \circ i'' is the identity of ''B''; #for every ''b \in B'', there are a neighborhood U \subseteq B of b and a neighbourhood V \subseteq E of i(b) such that i(U) \subseteq V, p(V) \subseteq U, V is homeomorphic to U\times \R^n and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dusa McDuff
Dusa McDuff FRS CorrFRSE (born 18 October 1945) is an English mathematician who works on symplectic geometry. She was the first recipient of the Ruth Lyttle Satter Prize in Mathematics, was a Noether Lecturer, and is a Fellow of the Royal Society. She is currently the Helen Lyttle Kimmel '42 Professor of Mathematics at Barnard College. Personal life and education Margaret Dusa Waddington was born in London, England, on 18 October 1945 to Edinburgh architect Margaret Justin Blanco White, second wife of biologist Conrad Hal Waddington, her father. Her sister is the anthropologist Caroline Humphrey, and she has an elder half-brother C. Jake Waddington by her father's first marriage. Her mother was the daughter of Amber Reeves, the noted feminist, author and lover of H. G. Wells. McDuff grew up in Scotland where her father was Professor of Genetics at the University of Edinburgh. McDuff was educated at St George's School for Girls in Edinburgh and, although the standard was lo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Švarc–Milnor Lemma
In the mathematical subject of geometric group theory, the Švarc–Milnor lemma (sometimes also called Milnor–Švarc lemma, with both variants also sometimes spelling Švarc as Schwarz) is a statement which says that a group G, equipped with a "nice" discrete isometric action on a metric space X, is quasi-isometric to X. This result goes back, in different form, before the notion of quasi-isometry was formally introduced, to the work of Albert S. Schwarz (1955) and John Milnor (1968). Pierre de la Harpe called the Švarc–Milnor lemma "the ''fundamental observation in geometric group theory''"Pierre de la Harpe, Topics in geometric group theory'. Chicago Lectures in Mathematics. University of Chicago Press, Chicago, IL, 2000. ; p. 87 because of its importance for the subject. Occasionally the name "fundamental observation in geometric group theory" is now used for this statement, instead of calling it the Švarc–Milnor lemma; see, for example, Theorem 8.2 in the book ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spectral Geometry
Spectral geometry is a field in mathematics which concerns relationships between geometric structures of manifolds and spectra of canonically defined differential operators. The case of the Laplace–Beltrami operator on a closed Riemannian manifold has been most intensively studied, although other Laplace operators in differential geometry have also been examined. The field concerns itself with two kinds of questions: direct problems and inverse problems. Inverse problems seek to identify features of the geometry from information about the eigenvalues of the Laplacian. One of the earliest results of this kind was due to Hermann Weyl who used David Hilbert's theory of integral equation in 1911 to show that the volume of a bounded domain in Euclidean space can be determined from the asymptotic behavior of the eigenvalues for the Dirichlet boundary value problem of the Laplace operator. This question is usually expressed as " Can one hear the shape of a drum?", the popular phras ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rokhlin's Theorem
In 4-dimensional topology, a branch of mathematics, Rokhlin's theorem states that if a smooth, orientable, closed 4-manifold ''M'' has a spin structure (or, equivalently, the second Stiefel–Whitney class w_2(M) vanishes), then the signature of its intersection form, a quadratic form on the second cohomology group H^2(M), is divisible by 16. The theorem is named for Vladimir Rokhlin, who proved it in 1952. Examples *The intersection form on ''M'' ::Q_M\colon H^2(M,\Z)\times H^2(M,\Z)\rightarrow \mathbb :is unimodular on \Z by Poincaré duality, and the vanishing of w_2(M) implies that the intersection form is even. By a theorem of Cahit Arf, any even unimodular lattice has signature divisible by 8, so Rokhlin's theorem forces one extra factor of 2 to divide the signature. *A K3 surface is compact, 4 dimensional, and w_2(M) vanishes, and the signature is −16, so 16 is the best possible number in Rokhlin's theorem. *A complex surface in \mathbb^3 of degree d is spin if ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surgery Theory
In mathematics, specifically in geometric topology, surgery theory is a collection of techniques used to produce one finite-dimensional manifold from another in a 'controlled' way, introduced by . Milnor called this technique ''surgery'', while Andrew H. Wallace, Andrew Wallace called it spherical modification. The "surgery" on a differentiable manifold ''M'' of dimension n=p+q+1, could be described as removing an imbedded sphere of dimension ''p'' from ''M''. Originally developed for differentiable (or, differentiable manifolds, smooth) manifolds, surgery techniques also apply to piecewise linear manifold, piecewise linear (PL-) and topological manifolds. Surgery refers to cutting out parts of the manifold and replacing it with a part of another manifold, matching up along the cut or boundary. This is closely related to, but not identical with, handlebody decompositions. More technically, the idea is to start with a well-understood manifold ''M'' and perform surgery on it to pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milnor–Wood Inequality
In mathematics, more specifically in differential geometry and geometric topology, the Milnor–Wood inequality is an obstruction to endow circle bundles over surfaces with a flat structure. It is named after John Milnor and John W. Wood. Flat bundles For linear bundles, flatness is defined as the vanishing of the curvature form of an associated connection. An arbitrary smooth (or topological) ''d''-dimensional fiber bundle is flat if it can be endowed with a foliation of codimension d that is transverse to the fibers. The inequality The Milnor–Wood inequality is named after two separate results that were proven by John Milnor and John W. Wood. Both of them deal with orientable circle bundles over a closed oriented surface \Sigma_g of positive genus ''g''. Theorem (Milnor, 1958) Let \pi\colon E \to \Sigma_g be a flat oriented linear circle bundle. Then the Euler number of the bundle satisfies , e(\pi), \leq g -1. Theorem (Wood, 1971) Let \pi\colon E \to \Sigma_g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plumbing (mathematics)
In the mathematical field of geometric topology, among the techniques known as surgery theory, the process of plumbing is a way to create new manifolds out of sphere bundle, disk bundles. It was first described by John Milnor and subsequently used extensively in surgery theory to produce manifolds and normal invariant, normal maps with given surgery obstructions. Definition Let \xi_i=(E_i,M_i,p_i) be a rank ''n'' vector bundle over an ''n''-dimensional Differentiable manifold, smooth manifold M_i for ''i'' = 1,2. Denote by D(E_i) the total space of the associated (closed) disk bundle D(\xi_i)and suppose that \xi_i, M_i and D(E_i)are oriented in a compatible way. If we pick two points x_i\in M_i, ''i'' = 1,2, and consider a ball neighbourhood of x_i in M_i, then we get neighbourhoods D^n_i\times D^n_i of the fibre over x_i in D(E_i). Let h:D^n_1\rightarrow D^n_2 and k:D^n_1\rightarrow D^n_2 be two diffeomorphisms (either both orientation preserving or revers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milnor–Thurston Kneading Theory
The Milnor–Thurston kneading theory is a mathematical theory which analyzes the iterates of piecewise monotone mappings of an interval into itself. The emphasis is on understanding the properties of the mapping that are invariant under topological conjugacy. The theory had been developed by John Milnor and William Thurston in two widely circulated and influential Princeton preprints from 1977 that were revised in 1981 and finally published in 1988. Applications of the theory include piecewise linear models, counting of fixed points, computing the total variation, and constructing an invariant measure with maximal entropy. Short description Kneading theory provides an effective calculus for describing the qualitative behavior of the iterates of a piecewise monotone mapping ''f'' of a closed interval ''I'' of the real line into itself. Some quantitative invariants of this discrete dynamical system, such as the ''lap numbers'' of the iterates and the Artin–Mazur zeta functi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algebraic Geometry
Algebraic geometry is a branch of mathematics which uses abstract algebraic techniques, mainly from commutative algebra, to solve geometry, geometrical problems. Classically, it studies zero of a function, zeros of multivariate polynomials; the modern approach generalizes this in a few different aspects. The fundamental objects of study in algebraic geometry are algebraic variety, algebraic varieties, which are geometric manifestations of solution set, solutions of systems of polynomial equations. Examples of the most studied classes of algebraic varieties are line (geometry), lines, circles, parabolas, ellipses, hyperbolas, cubic curves like elliptic curves, and quartic curves like lemniscate of Bernoulli, lemniscates and Cassini ovals. These are plane algebraic curves. A point of the plane lies on an algebraic curve if its coordinates satisfy a given polynomial equation. Basic questions involve the study of points of special interest like singular point of a curve, singular p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Singularity Theory
In mathematics, singularity theory studies spaces that are almost manifolds, but not quite. A string can serve as an example of a one-dimensional manifold, if one neglects its thickness. A singularity can be made by balling it up, dropping it on the floor, and flattening it. In some places the flat string will cross itself in an approximate "X" shape. The points on the floor where it does this are one kind of singularity, the double point: one bit of the floor corresponds to more than one bit of string. Perhaps the string will also touch itself without crossing, like an underlined "U". This is another kind of singularity. Unlike the double point, it is not ''stable'', in the sense that a small push will lift the bottom of the "U" away from the "underline". Vladimir Arnold defines the main goal of singularity theory as describing how objects depend on parameters, particularly in cases where the properties undergo sudden change under a small variation of the parameters. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
