Results 71 to 80 of about 601 (93)

Spectral flow as winding number and integral formulas [PDF]

arXiv, 2007
A general integral formula for the spectral flow of a path of unbounded selfadjoint Fredholm operators subject to certain summability conditions is derived from the interpretation of the spectral flow as a winding number.
arxiv  

Weak contractions and trace class perturbations

, 2007
An absolutely continuous contraction is said to be in the class A if it has isometric H∞ functional calculus. We present evidence in favor of the conjecture that the class A is invariant under trace-class perturbations. Mathematics subject classification
H. Bercovici, D. Timotin
semanticscholar   +1 more source

Trace ideals for pseudo-differential operators and their commutators with symbols in $α$-modulation spaces [PDF]

arXiv, 2007
In this paper, we consider the trace property of pseudo-differential operators with symbols in $\alpha$-modulation spaces.
arxiv  

On Factorization of a Perturbation of a J-selfadjoint Operator Arising in Fluid Dynamics [PDF]

arXiv, 2008
We prove that some perturbation of a J-selfadjoint second order differential operator admits factorization and use this new representation of the operator to prove compactness of its resolvent and to find its domain.
arxiv  

Infinite Hankel Block Matrices, Extremal Problems [PDF]

Oper.Theory:Adv.Appl. 202 (2010) 489-495, 2009
In this paper we use the matrix analogue of eigenvalue $\rho_{min}^{2}$ to formulate and to solve the extremal Nehary problem. When $\rho_{min}$ is a scalar, our approach coincides with Adamjan-Arov-Krein approach.
arxiv  

Lidskii-type formulae for Dixmier traces [PDF]

arXiv, 2010
We establish several analogues of the classical Lidskii Theorem for some special classes of singular traces (Dixmier traces and Connes-Dixmier traces) used in noncommutative geometry.
arxiv  

Norm closed operator ideals in Lorentz sequence spaces [PDF]

arXiv, 2011
In this paper, we study the structure of closed algebraic ideals in the algebra of operators acting on a Lorentz sequence space.
arxiv  

Duality theory for generalized summing linear operators [PDF]

arXiv, 2020
Generalizing classical results of the theory of absolutely summing operators, in this paper we characterize the duals of a quite large class of Banach operator ideals defined or characterized by the transformation of vector-valued sequences.
arxiv  

Boundedness for Pseudo-Differential Calculus on Nilpotent Lie Groups [PDF]

arXiv, 2012
We survey a few results on the boundedness of operators arising from the Weyl-Pedersen calculus associated with irreducible representations of nilpotent Lie groups.
arxiv  

Trace formulas for tuples of commuting contractions [PDF]

arXiv, 2013
This paper extends the trace formulas of [5] with perturbations in normed ideals of $B(H)$ to multivariate functions of commuting contractions admitting a dilation to commuting normal contractions.
arxiv