Sum Formula for SL$_2$ over a Totally Real Number Field

Sum Formula for SL$_2$ over a Totally Real Number Field PDF Author: Roelof W. Bruggeman
Publisher: American Mathematical Soc.
ISBN: 0821842021
Category : Mathematics
Languages : en
Pages : 96

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Book Description
The authors prove a general form of the sum formula $\mathrm{SL}_2$ over a totally real number field. This formula relates sums of Kloosterman sums to products of Fourier coefficients of automorphic representations. The authors give two versions: the spectral sum formula (in short: sum formula) and the Kloosterman sum formula. They have the independent test function in the spectral term, in the sum of Kloosterman sums, respectively.

Sum Formula for SL$_2$ over a Totally Real Number Field

Sum Formula for SL$_2$ over a Totally Real Number Field PDF Author: Roelof W. Bruggeman
Publisher: American Mathematical Soc.
ISBN: 0821842021
Category : Mathematics
Languages : en
Pages : 96

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Book Description
The authors prove a general form of the sum formula $\mathrm{SL}_2$ over a totally real number field. This formula relates sums of Kloosterman sums to products of Fourier coefficients of automorphic representations. The authors give two versions: the spectral sum formula (in short: sum formula) and the Kloosterman sum formula. They have the independent test function in the spectral term, in the sum of Kloosterman sums, respectively.

Ergodicity, Stabilization, and Singular Perturbations for Bellman-Isaacs Equations

Ergodicity, Stabilization, and Singular Perturbations for Bellman-Isaacs Equations PDF Author: Olivier Alvarez
Publisher: American Mathematical Soc.
ISBN: 0821847155
Category : Mathematics
Languages : en
Pages : 90

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Book Description
"Volume 204, number 960 (fourth of 5 numbers)."

Small Divisor Problem in the Theory of Three-Dimensional Water Gravity Waves

Small Divisor Problem in the Theory of Three-Dimensional Water Gravity Waves PDF Author: GŽrard Iooss
Publisher: American Mathematical Soc.
ISBN: 0821843826
Category : Science
Languages : en
Pages : 144

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Book Description
The authors consider doubly-periodic travelling waves at the surface of an infinitely deep perfect fluid, only subjected to gravity $g$ and resulting from the nonlinear interaction of two simply periodic travelling waves making an angle $2\theta$ between them. Denoting by $\mu =gL/c^{2}$ the dimensionless bifurcation parameter ( $L$ is the wave length along the direction of the travelling wave and $c$ is the velocity of the wave), bifurcation occurs for $\mu = \cos \theta$. For non-resonant cases, we first give a large family of formal three-dimensional gravity travelling waves, in the form of an expansion in powers of the amplitudes of two basic travelling waves. ``Diamond waves'' are a particular case of such waves, when they are symmetric with respect to the direction of propagation. The main object of the paper is the proof of existence of such symmetric waves having the above mentioned asymptotic expansion. Due to the occurence of small divisors, the main difficulty is the inversion of the linearized operator at a non trivial point, for applying the Nash Moser theorem. This operator is the sum of a second order differentiation along a certain direction, and an integro-differential operator of first order, both depending periodically of coordinates. It is shown that for almost all angles $\theta$, the 3-dimensional travelling waves bifurcate for a set of ``good'' values of the bifurcation parameter having asymptotically a full measure near the bifurcation curve in the parameter plane $(\theta,\mu ).$

Approximate Homotopy of Homomorphisms from $C(X)$ into a Simple $C^*$-Algebra

Approximate Homotopy of Homomorphisms from $C(X)$ into a Simple $C^*$-Algebra PDF Author: Huaxin Lin
Publisher: American Mathematical Soc.
ISBN: 0821851942
Category : Mathematics
Languages : en
Pages : 144

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Book Description
"Volume 205, number 963 (second of 5 numbers)."

Topological Automorphic Forms

Topological Automorphic Forms PDF Author: Mark Behrens
Publisher: American Mathematical Soc.
ISBN: 082184539X
Category : Mathematics
Languages : en
Pages : 167

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Book Description
The authors apply a theorem of J. Lurie to produce cohomology theories associated to certain Shimura varieties of type $U(1,n-1)$. These cohomology theories of topological automorphic forms ($\mathit{TAF}$) are related to Shimura varieties in the same way that $\mathit{TMF}$ is related to the moduli space of elliptic curves.

Unitary Invariants in Multivariable Operator Theory

Unitary Invariants in Multivariable Operator Theory PDF Author: Gelu Popescu
Publisher: American Mathematical Soc.
ISBN: 0821843966
Category : Mathematics
Languages : en
Pages : 105

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Book Description
This paper concerns unitary invariants for $n$-tuples $T:=(T_1,\ldots, T_n)$ of (not necessarily commuting) bounded linear operators on Hilbert spaces. The author introduces a notion of joint numerical radius and works out its basic properties. Multivariable versions of Berger's dilation theorem, Berger-Kato-Stampfli mapping theorem, and Schwarz's lemma from complex analysis are obtained. The author studies the joint (spatial) numerical range of $T$ in connection with several unitary invariants for $n$-tuples of operators such as: right joint spectrum, joint numerical radius, euclidean operator radius, and joint spectral radius. He also proves an analogue of Toeplitz-Hausdorff theorem on the convexity of the spatial numerical range of an operator on a Hilbert space, for the joint numerical range of operators in the noncommutative analytic Toeplitz algebra $F_n^\infty$.

Uniqueness and Stability in Determining a Rigid Inclusion in an Elastic Body

Uniqueness and Stability in Determining a Rigid Inclusion in an Elastic Body PDF Author: Antonino Morassi
Publisher: American Mathematical Soc.
ISBN: 0821843257
Category : Mathematics
Languages : en
Pages : 74

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Book Description
The authors consider the inverse problem of determining a rigid inclusion inside an isotropic elastic body $\Omega$, from a single measurement of traction and displacement taken on the boundary of $\Omega$. For this severely ill-posed problem they prove uniqueness and a conditional stability estimate of log-log type.

The Minimal Polynomials of Unipotent Elements in Irreducible Representations of the Classical Groups in Odd Characteristic

The Minimal Polynomials of Unipotent Elements in Irreducible Representations of the Classical Groups in Odd Characteristic PDF Author: Irina D. Suprunenko
Publisher: American Mathematical Soc.
ISBN: 0821843699
Category : Mathematics
Languages : en
Pages : 168

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Book Description
The minimal polynomials of the images of unipotent elements in irreducible rational representations of the classical algebraic groups over fields of odd characteristic are found. These polynomials have the form $(t-1)^d$ and hence are completely determined by their degrees. In positive characteristic the degree of such polynomial cannot exceed the order of a relevant element. It occurs that for each unipotent element the degree of its minimal polynomial in an irreducible representation is equal to the order of this element provided the highest weight of the representation is large enough with respect to the ground field characteristic. On the other hand, classes of unipotent elements for which in every nontrivial representation the degree of the minimal polynomial is equal to the order of the element are indicated. In the general case the problem of computing the minimal polynomial of the image of a given element of order $p^s$ in a fixed irreducible representation of a classical group over a field of characteristic $p>2$ can be reduced to a similar problem for certain $s$ unipotent elements and a certain irreducible representation of some semisimple group over the field of complex numbers. For the latter problem an explicit algorithm is given. Results of explicit computations for groups of small ranks are contained in Tables I-XII. The article may be regarded as a contribution to the programme of extending the fundamental results of Hall and Higman (1956) on the minimal polynomials from $p$-solvable linear groups to semisimple groups.

Cohomological Invariants: Exceptional Groups and Spin Groups

Cohomological Invariants: Exceptional Groups and Spin Groups PDF Author: Skip Garibaldi
Publisher: American Mathematical Soc.
ISBN: 0821844040
Category : Mathematics
Languages : en
Pages : 102

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Book Description
This volume concerns invariants of $G$-torsors with values in mod $p$ Galois cohomology--in the sense of Serre's lectures in the book Cohomological invariants in Galois cohomology--for various simple algebraic groups $G$ and primes $p$. The author determines the invariants for the exceptional groups $F_4$ mod 3, simply connected $E_6$ mod 3, $E_7$ mod 3, and $E_8$ mod 5. He also determines the invariants of $\mathrm{Spin}_n$ mod 2 for $n \leq 12$ and constructs some invariants of $\mathrm{Spin}_{14}$. Along the way, the author proves that certain maps in nonabelian cohomology are surjective. These surjectivities give as corollaries Pfister's results on 10- and 12-dimensional quadratic forms and Rost's theorem on 14-dimensional quadratic forms. This material on quadratic forms and invariants of $\mathrm{Spin}_n$ is based on unpublished work of Markus Rost. An appendix by Detlev Hoffmann proves a generalization of the Common Slot Theorem for 2-Pfister quadratic forms.

Regular Subgroups of Primitive Permutation Groups

Regular Subgroups of Primitive Permutation Groups PDF Author: Martin W. Liebeck
Publisher: American Mathematical Soc.
ISBN: 082184654X
Category : Mathematics
Languages : en
Pages : 87

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Book Description
Addresses the classical problem of determining finite primitive permutation groups G with a regular subgroup B.