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Chevalley's Structure Theorem
In algebraic geometry, Chevalley's structure theorem states that a smooth connected algebraic group over a perfect field has a unique normal smooth connected affine algebraic subgroup such that the quotient is an abelian variety. It was proved by (though he had previously announced the result in 1953), , and . Chevalley's original proof, and the other early proofs by Barsotti and Rosenlicht, used the idea of mapping the algebraic group to its Albanese variety. The original proofs were based on Weil's book Foundations of algebraic geometry and are hard to follow for anyone unfamiliar with Weil's foundations, but later gave an exposition of Chevalley's proof in scheme-theoretic terminology. Over non-perfect fields there is still a smallest normal connected linear subgroup such that the quotient is an abelian variety, but the linear subgroup need not be smooth. A consequence of Chevalley's theorem is that any algebraic group over a field is quasi-projective. Examples There are se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algebraic Geometry
Algebraic geometry is a branch of mathematics, classically studying zeros of multivariate polynomials. Modern algebraic geometry is based on the use of abstract algebraic techniques, mainly from commutative algebra, for solving geometrical problems about these sets of zeros. The fundamental objects of study in algebraic geometry are algebraic varieties, which are geometric manifestations of solutions of systems of polynomial equations. Examples of the most studied classes of algebraic varieties are: plane algebraic curves, which include lines, circles, parabolas, ellipses, hyperbolas, cubic curves like elliptic curves, and quartic curves like lemniscates and Cassini ovals. A point of the plane belongs to an algebraic curve if its coordinates satisfy a given polynomial equation. Basic questions involve the study of the points of special interest like the singular points, the inflection points and the points at infinity. More advanced questions involve the topology of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algebraic Group
In mathematics, an algebraic group is an algebraic variety endowed with a group structure which is compatible with its structure as an algebraic variety. Thus the study of algebraic groups belongs both to algebraic geometry and group theory. Many groups of geometric transformations are algebraic groups; for example, orthogonal groups, general linear groups, projective groups, Euclidean groups, etc. Many matrix groups are also algebraic. Other algebraic groups occur naturally in algebraic geometry, such as elliptic curves and Jacobian varieties. An important class of algebraic groups is given by the affine algebraic groups, those whose underlying algebraic variety is an affine variety; they are exactly the algebraic subgroups of the general linear group, and are therefore also called ''linear algebraic groups''. Another class is formed by the abelian varieties, which are the algebraic groups whose underlying variety is a projective variety. Chevalley's structure theorem states ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perfect Field
In algebra, a field ''k'' is perfect if any one of the following equivalent conditions holds: * Every irreducible polynomial over ''k'' has distinct roots. * Every irreducible polynomial over ''k'' is separable. * Every finite extension of ''k'' is separable. * Every algebraic extension of ''k'' is separable. * Either ''k'' has characteristic 0, or, when ''k'' has characteristic , every element of ''k'' is a ''p''th power. * Either ''k'' has characteristic 0, or, when ''k'' has characteristic , the Frobenius endomorphism is an automorphism of ''k''. * The separable closure of ''k'' is algebraically closed. * Every reduced commutative ''k''-algebra ''A'' is a separable algebra; i.e., A \otimes_k F is reduced for every field extension ''F''/''k''. (see below) Otherwise, ''k'' is called imperfect. In particular, all fields of characteristic zero and all finite fields are perfect. Perfect fields are significant because Galois theory over these fields becomes simpler, since the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Abelian Variety
In mathematics, particularly in algebraic geometry, complex analysis and algebraic number theory, an abelian variety is a projective algebraic variety that is also an algebraic group, i.e., has a group law that can be defined by regular functions. Abelian varieties are at the same time among the most studied objects in algebraic geometry and indispensable tools for much research on other topics in algebraic geometry and number theory. An abelian variety can be defined by equations having coefficients in any field; the variety is then said to be defined ''over'' that field. Historically the first abelian varieties to be studied were those defined over the field of complex numbers. Such abelian varieties turn out to be exactly those complex tori that can be embedded into a complex projective space. Abelian varieties defined over algebraic number fields are a special case, which is important also from the viewpoint of number theory. Localization techniques lead naturally fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albanese Variety
In mathematics, the Albanese variety A(V), named for Giacomo Albanese, is a generalization of the Jacobian variety of a curve. Precise statement The Albanese variety is the abelian variety A generated by a variety V taking a given point of V to the identity of A. In other words, there is a morphism from the variety V to its Albanese variety \operatorname(V), such that any morphism from V to an abelian variety (taking the given point to the identity) factors uniquely through \operatorname(V). For complex manifolds, defined the Albanese variety in a similar way, as a morphism from V to a torus \operatorname(V) such that any morphism to a torus factors uniquely through this map. (It is an analytic variety in this case; it need not be algebraic.) Properties For compact Kähler manifolds the dimension of the Albanese variety is the Hodge number h^, the dimension of the space of differentials of the first kind on V, which for surfaces is called the irregularity of a surface. In terms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Foundations Of Algebraic Geometry
''Foundations of Algebraic Geometry'' is a book by that develops algebraic geometry over field (mathematics), fields of any characteristic (algebra), characteristic. In particular it gives a careful treatment of intersection theory by defining the local intersection multiplicity of two Subvariety, subvarieties. Weil was motivated by the need for a rigorous theory of correspondences on algebraic curves in positive characteristic, which he used in his proof of the Riemann hypothesis for curves over a finite field. Weil introduced Abstract variety, abstract rather than Projective variety, projective varieties partly so that he could construct the Jacobian of a curve. (It was not known at the time that Jacobians are always projective varieties.) It was some time before anyone found any examples of complete variety, complete abstract varieties that are not projective. In the 1950s Weil's work was one of several competing attempts to provide satisfactory foundations for algebraic g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Generalized Jacobian
In algebraic geometry a generalized Jacobian is a commutative algebraic group associated to a curve with a divisor, generalizing the Jacobian variety of a complete curve. They were introduced by Maxwell Rosenlicht in 1954, and can be used to study ramified coverings of a curve, with abelian Galois group. Generalized Jacobians of a curve are extensions of the Jacobian of the curve by a commutative affine algebraic group, giving nontrivial examples of Chevalley's structure theorem. Definition Suppose ''C'' is a complete nonsingular curve, ''m'' an effective divisor on ''C'', ''S'' is the support of ''m'', and ''P'' is a fixed base point on ''C'' not in ''S''. The generalized Jacobian ''J''''m'' is a commutative algebraic group with a rational map ''f'' from ''C'' to ''J''''m'' such that: *''f'' takes ''P'' to the identity of ''J''''m''. *''f'' is regular outside ''S''. *''f''(''D'') = 0 whenever ''D'' is the divisor of a rational function ''g'' on ''C'' such that ''g''≡1 mod ''m''. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neron Model
Neron or Néron may refer to: * Neron (DC Comics), a fictional character in the DC Comics' universe. * An alternative name of the Roman Emperor Nero * André Néron, a mathematician, who introduced: ** Néron minimal model ** Néron differential ** Néron–Severi group ** Néron–Ogg–Shafarevich criterion ** Néron–Tate height * Geneviève Néron, a Canadian actress and musician * Néron, Eure-et-Loir, a commune in the Eure-et-Loir department of France * Néron, a village in the commune of Amanlis in the Ille-et-Vilaine department of France, located in the region of Brittany * NOAA's Environmental Real-time Observation Network (NERON), the US Weather Observation Network * ''Néron'' (opera) by Anton Rubinstein See also * Nero (other) Nero (37–68) was ''emperor'' of the ''Roman Empire'' from 54 to 68. Nero may also refer to: People *Any male member of the ''Claudii Nerones'' family of gens Claudia may be called Nero to distinguish them from other clan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Néron–Ogg–Shafarevich Criterion
In mathematics, the Néron–Ogg–Shafarevich criterion states that if ''A'' is an elliptic curve or abelian variety over a local field ''K'' and ℓ is a prime not dividing the characteristic of the residue field of ''K'' then ''A'' has good reduction if and only if the ℓ-adic Tate module ''T''ℓ of ''A'' is unramified. introduced the criterion for elliptic curves. used the results of to extend it to abelian varieties, and named the criterion after Ogg, Néron and Igor Shafarevich Igor Rostislavovich Shafarevich (russian: И́горь Ростисла́вович Шафаре́вич; 3 June 1923 – 19 February 2017) was a Soviet and Russian mathematician who contributed to algebraic number theory and algebraic geometry. ... (commenting that Ogg's result seems to have been known to Shafarevich). References * * * Abelian varieties Elliptic curves Theorems in algebraic geometry Arithmetic geometry {{Abstract-algebra-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Journal Of Mathematics
The ''American Journal of Mathematics'' is a bimonthly mathematics journal published by the Johns Hopkins University Press. History The ''American Journal of Mathematics'' is the oldest continuously published mathematical journal in the United States, established in 1878 at the Johns Hopkins University by James Joseph Sylvester, an English-born mathematician who also served as the journal's editor-in-chief from its inception through early 1884. Initially W. E. Story was associate editor in charge; he was replaced by Thomas Craig in 1880. For volume 7 Simon Newcomb became chief editor with Craig managing until 1894. Then with volume 16 it was "Edited by Thomas Craig with the Co-operation of Simon Newcomb" until 1898. Other notable mathematicians who have served as editors or editorial associates of the journal include Frank Morley, Oscar Zariski, Lars Ahlfors, Hermann Weyl, Wei-Liang Chow, S. S. Chern, André Weil, Harish-Chandra, Jean Dieudonné, Henri Cartan, Stephen S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algebraic Groups
In mathematics, an algebraic group is an algebraic variety endowed with a group structure which is compatible with its structure as an algebraic variety. Thus the study of algebraic groups belongs both to algebraic geometry and group theory. Many groups of geometric transformations are algebraic groups; for example, orthogonal groups, general linear groups, projective groups, Euclidean groups, etc. Many matrix groups are also algebraic. Other algebraic groups occur naturally in algebraic geometry, such as elliptic curves and Jacobian varieties. An important class of algebraic groups is given by the affine algebraic groups, those whose underlying algebraic variety is an affine variety; they are exactly the algebraic subgroups of the general linear group, and are therefore also called ''linear algebraic groups''. Another class is formed by the abelian varieties, which are the algebraic groups whose underlying variety is a projective variety. Chevalley's structure theorem s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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