The Positive Supercyclicity Theorem.
We present some recent results related with supercyclic operators, also some of its consequences. We will finalize with new related questions.
We present some recent results related with supercyclic operators, also some of its consequences. We will finalize with new related questions.
In this talk we explain a simple treatment of the quantum Birkhoff normal form for semiclassical pseudo-differential operators with smooth coefficients. The normal form is applied to describe the discrete spectrum in a generalised non-degenerate potential well, yielding uniform estimates in the energy . This permits a detailed study of the spectrum in various asymptotic regions of the parameters , and gives improvements and new proofs for many of the results in the field. In the completely resonant...
We consider the solution operator to the -operator restricted to forms with coefficients in . Here denotes -forms with coefficients in , is the corresponding -space and is a suitable rotation-invariant absolutely continuous finite measure. We will develop a general solution formula to . This solution operator will have the property . As an application of the solution formula we will be able to characterize compactness of the solution operator in terms of compactness of commutators...
The questions when a derivation on a Jordan-Banach algebra has quasi-nilpotent values, and when it has the range in the radical, are discussed.
The aim of this paper is to prove the statement announced in the title which can be reformulated in the following way. Let H be a separable infinite-dimensional Hilbert space and let Φ: B(H) → B(H) be a continuous linear mapping with the property that for every A ∈ B(H) there exists a sequence of automorphisms of B(H) (depending on A) such that . Then Φ is an automorphism. Moreover, a similar statement holds for the set of all surjective isometries of B(H).
It is shown that the sum and the product of two commuting Banach space operators with Dunford’s property have the single-valued extension property.
We solve, in two dimensions, the "square root problem of Kato". That is, for L ≡ -div (A(x)∇), where A(x) is a 2 x 2 accretive matrix of bounded measurable complex coefficients, we prove that L1/2: L12(R2) → L2(R2).[Proceedings of the 6th International Conference on Harmonic Analysis and Partial Differential Equations, El Escorial (Madrid), 2002].