Loop Groups, Discrete Versions of Some Classical Integrable Systems, and Rank 2 Extensions

Loop Groups, Discrete Versions of Some Classical Integrable Systems, and Rank 2 Extensions PDF Author: Percy Deift
Publisher:
ISBN: 9781470400569
Category : Hamiltonian systems
Languages : en
Pages : 101

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Book Description

Loop Groups, Discrete Versions of Some Classical Integrable Systems, and Rank 2 Extensions

Loop Groups, Discrete Versions of Some Classical Integrable Systems, and Rank 2 Extensions PDF Author: Percy Deift
Publisher:
ISBN: 9781470400569
Category : Hamiltonian systems
Languages : en
Pages : 101

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Book Description


Loop Groups, Discrete Versions of Some Classical Integrable Systems, and Rank 2 Extensions

Loop Groups, Discrete Versions of Some Classical Integrable Systems, and Rank 2 Extensions PDF Author: Percy Deift
Publisher: American Mathematical Soc.
ISBN: 0821825402
Category : Mathematics
Languages : en
Pages : 114

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Book Description
The authors show how to interpret recent results of Moser and Veselov on discrete versions of a class of classical integrable systems, in terms of a loop group framework. In this framework the discrete systems appear as time-one maps of integrable Hamiltonian flows. Earlier results of Moser on isospectral deformations of rank 2 extensions of a fixed matrix, can also be incorporated into their scheme.

Separatrix Surfaces and Invariant Manifolds of a Class of Integrable Hamiltonian Systems and Their Perturbations

Separatrix Surfaces and Invariant Manifolds of a Class of Integrable Hamiltonian Systems and Their Perturbations PDF Author: Jaume Llibre
Publisher: American Mathematical Soc.
ISBN: 082182581X
Category : Mathematics
Languages : en
Pages : 206

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Book Description
This work presents a study of the foliations of the energy levels of a class of integrable Hamiltonian systems by the sets of constant energy and angular momentum. This includes a classification of the topological bifurcations and a dynamical characterization of the criticalleaves (separatrix surfaces) of the foliation. Llibre and Nunes then consider Hamiltonain perturbations of this class of integrable Hamiltonians and give conditions for the persistence of the separatrix structure of the foliations and for the existence of transversal ejection-collision orbits of the perturbed system. Finally, they consider a class of non-Hamiltonian perturbations of a family of integrable systems of the type studied earlier and prove the persistence of "almost all" the tori and cylinders that foliate the energy levels of the unperturbed system as a consequence of KAM theory.

Extension of Positive-Definite Distributions and Maximum Entropy

Extension of Positive-Definite Distributions and Maximum Entropy PDF Author: Jean-Pierre Gabardo
Publisher: American Mathematical Soc.
ISBN: 0821825518
Category : Mathematics
Languages : en
Pages : 111

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Book Description
In this work, the maximum entropy method is used to solve the extension problem associated with a positive-definite function, or distribution, defined on an interval of the real line. Garbardo computes explicitly the entropy maximizers corresponding to various logarithmic integrals depending on a complex parameter and investigates the relation to the problem of uniqueness of the extension. These results are based on a generalization, in both the discrete and continuous cases, of Burg's maximum entropy theorem.

An Extension of the Galois Theory of Grothendieck

An Extension of the Galois Theory of Grothendieck PDF Author: André Joyal
Publisher: American Mathematical Soc.
ISBN: 0821823124
Category : Mathematics
Languages : en
Pages : 87

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Book Description
In this paper we compare, in a precise way, the concept of Grothendieck topos to the classical notion of topological space. The comparison takes the form of a two-fold extension of the idea of space.

Littlewood-Paley Theory on Spaces of Homogeneous Type and the Classical Function Spaces

Littlewood-Paley Theory on Spaces of Homogeneous Type and the Classical Function Spaces PDF Author: Yongsheng Han
Publisher: American Mathematical Soc.
ISBN: 0821825925
Category : Mathematics
Languages : en
Pages : 138

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Book Description
In this work, Han and Sawyer extend Littlewood-Paley theory, Besov spaces, and Triebel-Lizorkin spaces to the general setting of a space of homogeneous type. For this purpose, they establish a suitable analogue of the Calder 'on reproducing formula and use it to extend classical results on atomic decomposition, interpolation, and T1 and Tb theorems. Some new results in the classical setting are also obtained: atomic decompositions with vanishing b-moment, and Littlewood-Paley characterizations of Besov and Triebel-Lizorkin spaces with only half the usual smoothness and cancellation conditions on the approximate identity.

Computation and Combinatorics in Dynamics, Stochastics and Control

Computation and Combinatorics in Dynamics, Stochastics and Control PDF Author: Elena Celledoni
Publisher: Springer
ISBN: 3030015939
Category : Mathematics
Languages : en
Pages : 734

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Book Description
The Abel Symposia volume at hand contains a collection of high-quality articles written by the world’s leading experts, and addressing all mathematicians interested in advances in deterministic and stochastic dynamical systems, numerical analysis, and control theory. In recent years we have witnessed a remarkable convergence between individual mathematical disciplines that approach deterministic and stochastic dynamical systems from mathematical analysis, computational mathematics and control theoretical perspectives. Breakthrough developments in these fields now provide a common mathematical framework for attacking many different problems related to differential geometry, analysis and algorithms for stochastic and deterministic dynamics. In the Abel Symposium 2016, which took place from August 16-19 in Rosendal near Bergen, leading researchers in the fields of deterministic and stochastic differential equations, control theory, numerical analysis, algebra and random processes presented and discussed the current state of the art in these diverse fields. The current Abel Symposia volume may serve as a point of departure for exploring these related but diverse fields of research, as well as an indicator of important current and future developments in modern mathematics.

Random Perturbations of Hamiltonian Systems

Random Perturbations of Hamiltonian Systems PDF Author: Mark Iosifovich Freĭdlin
Publisher: American Mathematical Soc.
ISBN: 0821825860
Category : Mathematics
Languages : en
Pages : 97

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Book Description
Random perturbations of Hamiltonian systems in Euclidean spaces lead to stochastic processes on graphs, and these graphs are defined by the Hamiltonian. In the case of white-noise type perturbations, the limiting process will be a diffusion process on the graph. Its characteristics are expressed through the Hamiltonian and the characteristics of the noise. Freidlin and Wentzell calculate the process on the graph under certain conditions and develop a technique which allows consideration of a number of asymptotic problems. The Dirichlet problem for corresponding elliptic equations with a small parameter are connected with boundary problems on the graph.

Unraveling the Integral Knot Concordance Group

Unraveling the Integral Knot Concordance Group PDF Author: Neal W. Stoltzfus
Publisher: American Mathematical Soc.
ISBN: 082182192X
Category : Mathematics
Languages : en
Pages : 103

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Book Description
The group of concordance classes of high dimensional homotopy spheres knotted in codimension two in the standard sphere has an intricate algebraic structure which this paper unravels. The first level of invariants is given by the classical Alexander polynomial. By means of a transfer construction, the integral Seifert matrices of knots whose Alexander polynomial is a power of a fixed irreducible polynomial are related to forms with the appropriate Hermitian symmetry on torsion free modules over an order in the algebraic number field determined by the Alexander polynomial. This group is then explicitly computed in terms of standard arithmetic invariants. In the symmetric case, this computation shows there are no elements of order four with an irreducible Alexander polynomial. Furthermore, the order is not necessarily Dedekind and non-projective modules can occur. The second level of invariants is given by constructing an exact sequence relating the global concordance group to the individual pieces described above. The integral concordance group is then computed by a localization exact sequence relating it to the rational group computed by J. Levine and a group of torsion linking forms.

Degenerate Principal Series for Symplectic Groups

Degenerate Principal Series for Symplectic Groups PDF Author: Chris Jantzen
Publisher: American Mathematical Soc.
ISBN: 0821825496
Category : Mathematics
Languages : en
Pages : 130

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Book Description
This paper is concerned with induced representations for $p$-adic groups. In particular, Jantzen examines the question of reducibility in the case where the inducing subgroup is a maximal parabolic subgroup of $Sp_{2n (F)$ and the inducing representation is one-dimensional. Two different approaches to this problem are used. The first, based on the work of Casselman and of Gustafson, reduces the problem to the corresponding question about an associated finite-dimensional representation of a certain Hecke algebra. The second approach is based on a technique of Tadi\'c and involves an analysis of Jacquet modules. This is used to obtain a more general result on induced representations, which may be used to deal with the problem when the inducing representation satisfies a regularity condition. The same basic argument is also applied in a case-by-case fashion to nonregular cases.