共查询到10条相似文献,搜索用时 203 毫秒
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In this paper we give criteria for an ideal of a TAF algebra to be meet-irreducible. We show that is meet-irreducible if and only if the C∗-envelope of is primitive. In that case, admits a faithful nest representation which extends to a ∗-representation of the C∗-envelope for . We also characterize the meet-irreducible ideals as the kernels of bounded nest representations; this settles the question of whether the n-primitive and meet-irreducible ideals coincide. 相似文献
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We estimate the norm of the almost Mathieu operator , regarded as an element in the rotation C*-algebra . In the process, we prove for every λ∈R and the inequality
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Michael Roitman 《Advances in Mathematics》2003,176(1):53-88
In this paper, we develop a formalism for working with representations of vertex and conformal algebras by generalized fields—formal power series involving non-integer powers of the variable. The main application of our technique is the construction of a large family of representations for the vertex superalgebra corresponding to an integer lattice Λ. For an automorphism coming from a finite-order automorphism we find the conditions for existence of twisted modules of . We show that the category of twisted representations of is semisimple with finitely many isomorphism classes of simple objects. 相似文献
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Let γ be the Gauss measure on and the Ornstein-Uhlenbeck operator. For every p in [1,∞)?{2}, set , and consider the sector . The main results of this paper are the following. If p is in (1,∞)?{2}, and , i.e., if M is an Lp(γ)uniform spectral multiplier of in our terminology, and M is continuous on , then M extends to a bounded holomorphic function on the sector . Furthermore, if p=1 a spectral multiplier M, continuous on , satisfies the condition if and only if M extends to a bounded holomorphic function on the right half-plane, and its boundary value M(i·) on the imaginary axis is the Euclidean Fourier transform of a finite Borel measure on the real line. We prove similar results for uniform spectral multipliers of second order elliptic differential operators in divergence form on belonging to a wide class, which contains . From these results we deduce that operators in this class do not admit an H∞ functional calculus in sectors smaller than . 相似文献
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Joachim Toft 《Bulletin des Sciences Mathématiques》2003,127(2):101-132
We study , of all such that for every ?∈C∞0, where denotes the twisted convolution. We prove that certain boundedness for are completely determined of the behaviour for a at origin, for example that , and that if a(0)<∞, then a∈L2∩L∞. We use the results in order to determine wether positive pseudo-differential operators belong to certain Schatten-casses or not. 相似文献
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