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作者:Olmos, C
摘要:We give a geometric proof of the Berger Holonomy Theorem. The proof uses Euclidean submanifold geometry of orbits and gives a link between Riemannian holonomy groups and normal holonomy groups.
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作者:Chlebík, M; Cianchi, A; Fusco, N
摘要:Steiner symmetrization is known not to increase perimeter of sets in R-n. The sets whose perimeter is preserved under this symmetrization are characterized in the present paper.
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作者:Knutson, A; Miller, E
摘要:Given a permutation w is an element of S-n, we consider a determinantal ideal I-w whose generators are certain minors in the generic n x n matrix (filled with independent variables). Using 'multidegrees' as simple algebraic substitutes for torus-equivariant cohomology classes on vector spaces, our main theorems describe, for each ideal I-w: variously graded multidegrees and Hilbert series in terms of ordinary and double Schubert and Grothendieck polynomials; a Grobner basis consisting of minor...
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作者:Eskin, A; Margulis, G; Mozes, S
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作者:Hales, TC
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作者:Horváth, M
摘要:Consider the inverse eigenvalue problem of the Schrodinger operator defined on a finite interval. We give optimal and almost optimal conditions for a set of eigenvalues to determine the Schrodinger operator. These conditions are simple closedness properties of the exponential system corresponding to the known eigenvalues. The statements contain nearly all former results of this topic. We give also conditions for recovering the Weyl-Titchmarsh m-function from its values m(lambda(n)).
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作者:Klainerman, S; Rodnianski, I
摘要:This is the first in a series of papers in which we initiate the study of very rough solutions to the initial value problem for the Einstein-vacuum equations expressed relative to wave coordinates. By very rough we mean solutions which cannot be constructed by the classical techniques of energy estimates and Sobolev inequalities. Following [Kl-Ro] we develop new analytic methods based on Strichartz-type inequalities which result in a gain of half a derivative relative to the classical result. ...
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作者:Bestvina, M; Feighn, M; Handel, M
摘要:This is the second of two papers in which we prove the Tits alternative for Out(F-n).
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作者:Johnson, WB; Odell, E
摘要:We prove that if X is a separable infinite dimensional Banach space then its isomorphism class has,infinite diameter with respect to the Banach-Mazur distance. One step in the proof is to show that if X is elastic then X contains an isomorph of c(0). We call X elastic if for some K < infinity for every Banach space Y which embeds into X, the space Y is K-isomorphic to a subspace of X. We also prove that if X is a separable Banach space such that for some K < infinity every isomorph of X is K-e...
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作者:Bochi, J; Viana, M
摘要:We show that the integrated Lyapunov exponents of C-1 volume-preserving diffeomorphisms are simultaneously continuous at a given diffeomorphism only if the corresponding Oseledets splitting is trivial (all Lyapunov exponents are equal to zero) or else dominated (uniform hyperbolicity in the projective bundle) almost everywhere. We deduce a sharp dichotomy for generic volume-preserving diffeomorphisms on any compact manifold: almost every orbit either is projectively hyperbolic or has all Lyapu...