Basic Global Relative Invariants for Nonlinear Differential Equations

Basic Global Relative Invariants for Nonlinear Differential Equations PDF Author: Roger Chalkley
Publisher:
ISBN: 9781470404949
Category : Differential equations, Nonlinear
Languages : en
Pages : 0

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Basic Global Relative Invariants for Nonlinear Differential Equations

Basic Global Relative Invariants for Nonlinear Differential Equations PDF Author: Roger Chalkley
Publisher:
ISBN: 9781470404949
Category : Differential equations, Nonlinear
Languages : en
Pages : 0

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Book Description


Random Sets and Invariants for (Type II) Continuous Tensor Product Systems of Hilbert Spaces

Random Sets and Invariants for (Type II) Continuous Tensor Product Systems of Hilbert Spaces PDF Author: Volkmar Liebscher
Publisher: American Mathematical Soc.
ISBN: 0821843184
Category : Mathematics
Languages : en
Pages : 124

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Book Description
In a series of papers Tsirelson constructed from measure types of random sets or (generalised) random processes a new range of examples for continuous tensor product systems of Hilbert spaces introduced by Arveson for classifying $E_0$-semigroups upto cocycle conjugacy. This paper starts from establishing the converse. So the author connects each continuous tensor product system of Hilbert spaces with measure types of distributions of random (closed) sets in $[0,1]$ or $\mathbb R_+$. These measure types are stationary and factorise over disjoint intervals. In a special case of this construction, the corresponding measure type is an invariant of the product system. This shows, completing in a more systematic way the Tsirelson examples, that the classification scheme for product systems into types $\mathrm{I}_n$, $\mathrm{II}_n$ and $\mathrm{III}$ is not complete. Moreover, based on a detailed study of this kind of measure types, the author constructs for each stationary factorising measure type a continuous tensor product system of Hilbert spaces such that this measure type arises as the before mentioned invariant.

Invariant Differential Operators for Quantum Symmetric Spaces

Invariant Differential Operators for Quantum Symmetric Spaces PDF Author: Gail Letzter
Publisher: American Mathematical Soc.
ISBN: 0821841319
Category : Mathematics
Languages : en
Pages : 104

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Book Description
This paper studies quantum invariant differential operators for quantum symmetric spaces in the maximally split case. The main results are quantum versions of theorems of Harish-Chandra and Helgason: There is a Harish-Chandra map which induces an isomorphism between the ring of quantum invariant differential operators and the ring of invariants of a certain Laurent polynomial ring under an action of the restricted Weyl group. Moreover, the image of the center under this map is the entire invariant ring if and only if the underlying irreducible symmetric pair is not of four exceptional types. In the process, the author finds a particularly nice basis for the quantum invariant differential operators that provides a new interpretation of difference operators associated to Macdonald polynomials.

A Proof of Alon's Second Eigenvalue Conjecture and Related Problems

A Proof of Alon's Second Eigenvalue Conjecture and Related Problems PDF Author: Joel Friedman
Publisher: American Mathematical Soc.
ISBN: 0821842803
Category : Mathematics
Languages : en
Pages : 114

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Book Description
A $d$-regular graph has largest or first (adjacency matrix) eigenvalue $\lambda_1=d$. Consider for an even $d\ge 4$, a random $d$-regular graph model formed from $d/2$ uniform, independent permutations on $\{1,\ldots,n\}$. The author shows that for any $\epsilon>0$ all eigenvalues aside from $\lambda_1=d$ are bounded by $2\sqrt{d-1}\;+\epsilon$ with probability $1-O(n^{-\tau})$, where $\tau=\lceil \bigl(\sqrt{d-1}\;+1\bigr)/2 \rceil-1$. He also shows that this probability is at most $1-c/n^{\tau'}$, for a constant $c$ and a $\tau'$ that is either $\tau$ or $\tau+1$ (``more often'' $\tau$ than $\tau+1$). He proves related theorems for other models of random graphs, including models with $d$ odd.

Index Theory, Eta Forms, and Deligne Cohomology

Index Theory, Eta Forms, and Deligne Cohomology PDF Author: Ulrich Bunke
Publisher: American Mathematical Soc.
ISBN: 0821842846
Category : Mathematics
Languages : en
Pages : 134

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Book Description
This paper sets up a language to deal with Dirac operators on manifolds with corners of arbitrary codimension. In particular the author develops a precise theory of boundary reductions. The author introduces the notion of a taming of a Dirac operator as an invertible perturbation by a smoothing operator. Given a Dirac operator on a manifold with boundary faces the author uses the tamings of its boundary reductions in order to turn the operator into a Fredholm operator. Its index is an obstruction against extending the taming from the boundary to the interior. In this way he develops an inductive procedure to associate Fredholm operators to Dirac operators on manifolds with corners and develops the associated obstruction theory.

Bernoulli Free-Boundary Problems

Bernoulli Free-Boundary Problems PDF Author: Eugene Shargorodsky
Publisher: American Mathematical Soc.
ISBN: 0821841890
Category : Mathematics
Languages : en
Pages : 86

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Book Description
Questions of existence, multiplicity, and regularity of free boundaries for prescribed data need to be addressed and their solutions lead to nonlinear problems. In this paper an equivalence is established between Bernoulli free-boundary problems and a class of equations for real-valued functions of one real variable.

Complicial Sets Characterising the Simplicial Nerves of Strict $\omega $-Categories

Complicial Sets Characterising the Simplicial Nerves of Strict $\omega $-Categories PDF Author: Dominic Verity
Publisher: American Mathematical Soc.
ISBN: 0821841424
Category : Mathematics
Languages : en
Pages : 208

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Book Description
The primary purpose of this work is to characterise strict $\omega$-categories as simplicial sets with structure. The author proves the Street-Roberts conjecture in the form formulated by Ross Street in his work on Orientals, which states that they are exactly the ``complicial sets'' defined and named by John Roberts in his handwritten notes of that title (circa 1978). On the way the author substantially develops Roberts' theory of complicial sets itself and makes contributions to Street's theory of parity complexes. In particular, he studies a new monoidal closed structure on the category of complicial sets which he shows to be the appropriate generalisation of the (lax) Gray tensor product of 2-categories to this context. Under Street's $\omega$-categorical nerve construction, which the author shows to be an equivalence, this tensor product coincides with those of Steiner, Crans and others.

Minimal Resolutions via Algebraic Discrete Morse Theory

Minimal Resolutions via Algebraic Discrete Morse Theory PDF Author: Michael Jöllenbeck
Publisher: American Mathematical Soc.
ISBN: 0821842579
Category : Language Arts & Disciplines
Languages : en
Pages : 88

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Book Description
"January 2009, volume 197, number 923 (end of volume)."

The Beltrami Equation

The Beltrami Equation PDF Author: Tadeusz Iwaniec
Publisher: American Mathematical Soc.
ISBN: 0821840452
Category : Mathematics
Languages : en
Pages : 110

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Book Description
The measurable Riemann Mapping Theorem (or the existence theorem for quasiconformal mappings) has found a central role in a diverse variety of areas such as holomorphic dynamics, Teichmuller theory, low dimensional topology and geometry, and the planar theory of PDEs. Anticipating the needs of future researchers, the authors give an account of the state of the art as it pertains to this theorem, that is, to the existence and uniqueness theory of the planar Beltrami equation, and various properties of the solutions to this equation. The classical theory concerns itself with the uniformly elliptic case (quasiconformal mappings). Here the authors develop the theory in the more general framework of mappings of finite distortion and the associated degenerate elliptic equations.

Brownian Brownian Motion-I

Brownian Brownian Motion-I PDF Author: Nikolai Chernov
Publisher: American Mathematical Soc.
ISBN: 082184282X
Category : Science
Languages : en
Pages : 208

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Book Description
A classical model of Brownian motion consists of a heavy molecule submerged into a gas of light atoms in a closed container. In this work the authors study a 2D version of this model, where the molecule is a heavy disk of mass $M \gg 1$ and the gas is represented by just one point particle of mass $m=1$, which interacts with the disk and the walls of the container via elastic collisions. Chaotic behavior of the particles is ensured by convex (scattering) walls of the container. The authors prove that the position and velocity of the disk, in an appropriate time scale, converge, as $M\to\infty$, to a Brownian motion (possibly, inhomogeneous); the scaling regime and the structure of the limit process depend on the initial conditions. The proofs are based on strong hyperbolicity of the underlying dynamics, fast decay of correlations in systems with elastic collisions (billiards), and methods of averaging theory.