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Topic: Weight (representation theory)


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In the News (Wed 10 Feb 10)

  
  Weight (representation theory) - Wikipedia, the free encyclopedia
Weight is a concept arising often in representation theory of Lie groups and Lie algebras, a branch of mathematics.
The motivation is that, given a set S of complex matrices, each of which is diagonalizable and any two of which commute, it is always possible to diagonalize all the elements of S simultaneously.
Sometimes, the term dominant weight is used to denote a dominant (in the above sense) and integral weight.
en.wikipedia.org /wiki/Weight_(representation_theory)   (704 words)

  
 literary theory: an evaluation   (Site not responding. Last check: 2007-11-05)
Theory is there to help them should they need it, but its wider reaches and philosophical implications are not generally of interest.
For all its deficiencies, theory can focus attention on what writers should be trying to do, act as a prophylactic against the false and stultifying, and open up disciplines that support writing and are fascinating in their own right.
Theory at its most basic, those practical maxims that writers carry in their heads — maintain the viewpoint, shun cliché, employ the active tense — are applications of the aesthetic demands for pleasing shape and emotive appeal.
www.textetc.com /theory.html   (4904 words)

  
 Graph theory - Wikipedia, the free encyclopedia (via CobWeb/3.1 planet1.scs.cs.nyu.edu)   (Site not responding. Last check: 2007-11-05)
In mathematics and computer science, graph theory is the study of graphs, mathematical structures used to model pairwise relations between objects from a certain collection.
Graphs with weights, or weighted graphs, are used to represent structures in which pairwise connections have some numerical values.
A digraph with weighted edges in the context of graph theory is called a network.
en.wikipedia.org.cob-web.org:8888 /wiki/Graph_theory   (1306 words)

  
 [No title]   (Site not responding. Last check: 2007-11-05)
The first is to attain a deeper understanding of representations of p-adic groups by studying the behavior of affine Hecke algebras under extension of scalars.
Representation theory is a major mathematical technique for exploiting the presence of symmetry.
Another way of thinking about representation theory is as a generalization of the theory of eigenvalues and matrices that many people see in a college course on basic linear algebra.
www.cs.utexas.edu /users/yguan/NSFAbstracts/Abstracts/MPS/DMS.MPS.a9970626.txt   (227 words)

  
 Baby Weight -- Recommendations and Resources   (Site not responding. Last check: 2007-11-05)
An alternative measure of molecular weight for a polymer is the number average molecular weight; their ratio is called the polydispersity index.
Weight is the force exerted upon an object by virtue of its position in a gravitational field.
Must weight is a measure of the amount of sugar in grape juice (must), and hence the amount of alcohol that could potentially be produced if it is all fermented to alcohol, rather than left as residual sugar.
www.becomingapediatrician.com /health/10/baby-weight.html   (1134 words)

  
 Hexapedia - Weight (representation theory) (via CobWeb/3.1 planetlab2.netlab.uky.edu)   (Site not responding. Last check: 2007-11-05)
Given a set S of complex matrices, each of which is diagonalizable and any two of which commute under multiplication, it is always possible to diagonalize all the elements of S simultaneously.
This situation arises typically in the representation theory of Lie algebras.
This situation arises typically in the representation theory of compact Lie groups, where S is typically taken to be a maximal torus, i.e., a maximal compact connected commutative Lie group.
www.hexafind.com.cob-web.org:8888 /encyclopedia/Weight_(representation_theory)   (396 words)

  
 UIUC Number Theory: Faculty Research Descriptions
Beurling theory is concerned with properties of a collection of real numbers which has a multiplicative structure but not necessarily an additive one.
Trained as a number theorist, he is also interested in problems in analysis, probability theory, and combinatorics, and, in particular, in problems that lie at the interface of these areas with number theory.
She is currently interested in integrable models using the algebraic approach; representations of quantum affine algebras; and combinatorial representation theory of vertex operator algebras and conformal field theories.
www.math.uiuc.edu /ResearchAreas/numbertheory/facultyresearch.html   (3429 words)

  
 Springer Online Reference Works   (Site not responding. Last check: 2007-11-05)
The representation contragredient to a rational representation is a rational representation.
is finite, then each of its linear representations will be a rational representation, and the theory of rational representations coincides with the theory of representations of finite groups (cf.
To a large extent, specific methods of the theory of linear algebraic groups are used to study rational representations in case the group under consideration is connected, and the most thoroughly developed theory is that of rational representations of connected semi-simple algebraic groups.
eom.springer.de /R/r077630.htm   (501 words)

  
 Research - UNL - Department of Mathematics   (Site not responding. Last check: 2007-11-05)
Roger Wiegand works on the homology and representation theory of local rings: On the homological side, he studies depth properties of tensor products of modules and related questions on the vanishing of Tor.
In representation theory he is interested in the classification of rings of finite representation type and questions regarding uniqueness of direct-sum decompositions of modules.
She also works in representation theory and on the partially ordered set of prime ideals in Noetherian rings of low dimension.
www.math.unl.edu /pi/research/ca   (363 words)

  
 Gordon Ritter   (Site not responding. Last check: 2007-11-05)
The JMP paper begins a systematic study of channels defined by representations; the famous Werner-Holevo channel is one element of this infinite class.
We show that the channel derived from the defining representation of su(n) is a depolarizing channel for all n, but for most other representations this is not the case.
These theories have been proven to exist in the sense of constructive quantum field theory, and they also satisfy the assumptions used by Vafa and Cecotti in their study of the geometry of ground states.
www.people.fas.harvard.edu /~ritter/index.cgi?action=research   (855 words)

  
 Huajun's Homepage   (Site not responding. Last check: 2007-11-05)
Given a representation of a real or complex reductive Lie group G on V, a parabolic subgroup P imposes certain partial order (or grading) on V. One can describe the parabolic subgroup orbits and invariants on V by studying the structure of G in accordance with the partial order.
Representations of semisimple or reductive groups are linked to those of semisimple Lie algebras.
Representation theory as a vivid field has deep connections to many other branches of mathematics.
www.auburn.edu /~huanghu   (231 words)

  
 Mathematical Sciences Research Institute - Combinatorial Representation Theory   (Site not responding. Last check: 2007-11-05)
In representation theory, abstract algebraic structures are represented using matrices or geometry.
These representations provide a bridge between the abstract symbolic mathematics and its explicit applications in nearly every branch of mathematics as well as in related fields such as physics, chemistry, engineering, and statistics.
In the 21st century Combinatorial Representation Theory lives in the intersection of several fields: combinatorics, representation theory, analysis, algebraic geometry, Lie theory, and mathematical physics.
www.msri.org /calendar/programs/ProgramInfo/248/show_program   (436 words)

  
 MAT 290-016 Gromov-Witten Theory and Virasoro Constraints
Abstract: The GW theory is an intersection theory of cohomology classes on the moduli space of holomorphic maps from a Riemann surface into a symplectic manifold.
Besides representation theory of the Virasoro algebra itself, the "Virasoro constraint condition" appears in two places in mathematics: one is in Gromov-Witten theory, and the other in Borchards' theory of vertex (operator) algebras and Moonshine.
This representation is completely reducible and decomposes into the direct sum of irreducible highest weight representations with central charge c=1.
www.math.ucdavis.edu /~mulase/courses/mat290GW.html   (683 words)

  
 Highest weight representation and lowest weight representation... - Wikipedia, the free encyclopedia
Please search for Highest weight representation and lowest weight representation...
Start the Highest weight representation and lowest weight representation...
Look for "Highest weight representation and lowest weight representation...
en.wikipedia.org /wiki/Highest_weight_representation_and_lowest_weight_representation...   (185 words)

  
 [No title]   (Site not responding. Last check: 2007-11-05)
In ordinary representation theory, one can recover a representation by starting with a high weight vector and hitting it with lowering operators until all further applications are the zero vector.
A high weight vector is recognizable as one that raises to zero under all simple roots.
The number of paths with a given endpoint nu is the dimension of the mu weight space in the representation lambda.
alumnus.caltech.edu /~allenk/java/LittelmannPaths/index.html   (1002 words)

  
 Workshop on Representation Theory and Geometry 2005
A crucial role in the theory of SRA associated with wreath-productsis is a construction of these algebras by means of quantum Hamiltonian reduction.
To study the representation theory of U, Drinfeld used the KZ-equations to construct a quasi-Hopf algebra A. He proved that particular categories of modules over the algebras U and A are tensor equivalent.
This modification is dictated by the representation theory of the double affine Hecke algebra.
math.berkeley.edu /~bwebste/workshop2005.html   (999 words)

  
 BOMBAY LECTURES ON HIGHEST WEIGHT REPRESENTATIONS OF INFINITE DIMENSIONAL LIE ALGEBRAS
The third is the unitary highest weight representations of the current (= affine Kac-Moody) algebras.
These algebras appear in the lectures twice, in the reduction theory of soliton equations (KP KdV) and in the Sugawara construction as the main tool in the study of the fourth incarnation of the main idea, the theory of the highest weight representations of the Virasoro algebra.
To mathematicians, it illustrates the interaction of the key ideas of the representation theory of infinite-dimensional Lie algebras; and to physicists, this theory is turning into an important component of such domains of theoretical physics as soliton theory, theory of two-dimensional statistical models, and string theory.
www.worldscibooks.com /mathematics/0476.html   (262 words)

  
 [No title]   (Site not responding. Last check: 2007-11-05)
Title : Mathematical Sciences: Weights for Representations of Finite Groups Abstract : This project is concerned with the representation theory of finite groups.
He will also study the general modular representation theory of Hecke algebras for arbitrary finite groups and will study coefficient systems on some simplicial complexes related to group structure.
This project is in the general area of representation theory of finite groups.
www.cs.utexas.edu /users/yguan/NSFAbstracts/Abstracts/MPS/DMS.MPS.a9101543.txt   (108 words)

  
 geoms05   (Site not responding. Last check: 2007-11-05)
I will focus on the geometric approach to the finite dimensional representation theory of the group SL(2,C) of invertible two-by-two matrices with complex entries having determinant equal to one.
I will, using mainly the example of sl(2), give a rapid introduction to the highest weight (infinite dimensional) representation theory (of a reductive Lie algebra) and the corresponding geometric representation theory (which describes this representation theory in terms of D-modules [= systems of linear PDE with rational coefficients] on the flag variety).
Again these results extend to the weighted case and again the proof depends on the study of a toric degeneration.
math.arizona.edu /~foth/geoms05.html   (1665 words)

  
 Two cheers for string theory | Cosmic Variance   (Site not responding. Last check: 2007-11-05)
String theory, with all of its difficulties, is by far the most promising route to one of the most long-lasting and ambitious goals of natural science: a complete understanding of the microscopic laws of nature.
Just as in quantum field theory, the observable spectrum of low-energy string excitations and their interactions (that is to say, particle physics) depends not only on the fundamental string physics, but on the specific vacuum state in which we find ourselves.
If string theorists continue to develop a really outdated theory at one hand and arrogantly claim that are doing (they believe that in their infinite ignorance) the most important, the most powerful, the most fundamental theory at the other, then they would feel comfortable with the mocking of their colleagues.
cosmicvariance.com /2005/07/21/two-cheers-for-string-theory   (15193 words)

  
 Crystal page   (Site not responding. Last check: 2007-11-05)
This is not the place for an exposition of representation theory, Lie algebras, or crystal graphs.
An irreducible representation is denoted by its highest dominant weight vector, written as a linear combination of the ei's.
For example, the identity representation of A3 is denoted e1 and its contragredient is denoted by e1+e2+e3.
web.usna.navy.mil /~wdj/crystal.htm   (1093 words)

  
 The Math Forum - Math Library - Number Theory   (Site not responding. Last check: 2007-11-05)
Papers from a Mathematics graduate from The University Of Sussex at Brighton: Number Theory: GCD and Prime Factorisation; Molien's Theorem, Invariant Theory and Gregor Kemper; A History of Equality.
In number theory, straightforward, reasonable questions are remarkably easy to ask, yet many of these questions are surprisingly difficult or even impossible to answer.
A connected series of four problems in elementary number theory that are ideal for discovery learning at several levels.
mathforum.org /library/topics/number_theory   (2144 words)

  
 Local Representation Theory - Cambridge University Press
Modular Representations as an Introduction to the Local Representation Theory of Finite Groups
The aim of this text is to present some of the key results in the representation theory of finite groups.
Representation theory is applied in number theory, combinatorics and in many areas of algebra.
www.cambridge.org /catalogue/catalogue.asp?isbn=052144926X   (293 words)

  
 Schur Algebras and Representation Theory - Cambridge University Press   (Site not responding. Last check: 2007-11-05)
Schur algebras are algebraic systems which provide a link between the representation theory of the symmetric and general linear groups (both finite and infinite).
He discusses the usual representation-theoretic topics such as constructions of irreducible modules, the blocks containing them, their modular characters and the problem of computing decomposition numbers; moreover deeper properties such as the quasi-hereditariness of the Schur algebra are also considered.
A few topics however require results from the representation theory of algebraic groups, so, to keep the book reasonably self-contained, an appendix on that is included.
www.cambridge.org /catalogue/catalogue.asp?ISBN=0521415918   (213 words)

  
 Representation Theory
The construction admits a (conjectural) generalization to the case where the flag manifold is replaced by the zero set of a nilpotent vector field.
N. Chriss and V. Ginzburg, Representation theory and complex geometry, Birkhäuser, Boston-Basel-Berlin, 1997.
J.C. Jantzen, Representations of Lie algebras in prime characteristic, lectures at the Montréal Summer School 1997.
www.ams.org /ert/1998-002-09/S1088-4165-98-00054-5/home.html   (342 words)

  
 Lie Algebra Weight -- from Wolfram MathWorld
are called weight vectors, and the corresponding eigenspaces are called weight spaces.
In the important special case of the adjoint representation of a semisimple Lie algebra, the weights are called Lie algebra roots and the weight space is called the root space.
The set of all possible weights forms a weight lattice, which contains the root lattice.
mathworld.wolfram.com /LieAlgebraWeight.html   (170 words)

  
 weight - OneLook Dictionary Search
noun: sports equipment used in calisthenic exercises and weightlifting; a weight that is not attached to anything and is raised and lowered by use of the hands and arms
Phrases that include weight: molecular weight, equivalent weight, troy weight, avoirdupois weight, net weight, more...
Words similar to weight: angle, burden, burthen, slant, weighted, weighting, exercising weight, heft, onus, system of weights, ton, weight down, weight unit, more...
www.onelook.com /?w=weight   (541 words)

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