To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure no-reply@cambridge.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
This monograph has grown out of a recent sequel of jointly written papers by the authors. It proposes to present a unified treatment of the local spectral theory for closed operators acting on a complex Banach space.
While working with closed operators, in a few instances it will be unavoidable to transgress the former concept. More to the point, the theory makes frequent use of operators coinduced by closed operators on a quotient space. Such operators, in general, are not even closable. Special efforts will be requested to exhibit conditions which make them, at least, closable and hence useful instruments in the subsequent theory.
The plan of this work may be sketched as follows. After a brief presentation of the spectral decomposition problem, Chapter I introduces the notion of the single valued extension property with some of its implications. Subsequently, a general study of invariant subspaces is followed by the developing ideas for some special types of subspaces, such as v-spaces, μ-spaces, analytically invariant subspaces, T-absorbent spaces, spectral maximal and T-bounded spectral maximal spaces, T being the given closed operator.
With Chapter II we come to the essence of the spectral theory: the general type of spectral decomposition property with its relationship to the unbounded decomposable operators.
Chapter III is devoted to the spectral duality theory. After having overcome some difficulties due to the general type of the spectral decomposition problem, it was gratifying to have obtained a spectral duality theorem, under the natural constraints of the problem.
In the Notes and Comments on Chapter IV (p.106), a diagram of implications between various types of spectral resolvents is given. Are there more implications? Specifically:
PROBLEM 1. Is every spectral resolvent of a given operator monotonic? Is every spectral resolvent analytically invariant?
PROBLEM 2. Is every monotonic spectral resolvent strongly monotonic? Is every monotonic spectral resolvent analytically invariant? Is every almost localized spectral resolvent a strong spectral resolvent? Is every almost localized spectral resolvent analytically invariant?
In [W.a] it was shown that there exists a complex Banach space X and an operator T ∈ B(X), which is decomposable, the adjoint T* is strongly decomposable but T is not strongly decomposable. This gives rise to
PROBLEM 3. Does it exist a complex Banach space X and a strongly decomposable T ∈ B(X), with T* decomposable but not strongly decomposable?
PROBLEM 4. Is it true that T is strongly decomposable iff T** is strongly decomposable?
In the study of operators with the SDI, Corollary 17.10 asserts that if a closed operator is endowed with the SDI then it has the SSDP. What about the converse?
Suppose that f(z) is non-constant and meromorphic in the plane and that, for some k≥= 1, a0(z),…, ak(z) are meromorphic in the plane with
for j' = 0,…, k. Here, using standard notation from [3], S(r,f) denotes any quantity satisfying S(r,f) = o(T(r,f)) as r→ ∞, possibly outside a set of finite linear measure. Then, setting
we have ([3, p. 57])
Theorem A. Suppose that f(z) is non-constant and meromorphic in the plane, and thatψ (z) given by (1.2) and (1.1) and is non-constant. Then
where N0(r, l/ψ') counts only zeros of ψ' which are not zeros of ψ − 1, and thecounting functions count points without regard to multiplicity.
The asymptotic behaviour of a sequence of polynomials cm = cm(v) satisfying
is established. These polynomials occur in Hawkins' formula for the residues of a Bessel-zeta function at its possible poles in the left half plane. The results imply that cm(v)/cm(0) converges uniformly to cos πV on compact sets. This in turn implies that, for v not a half odd integer, all but finitely many of the possible poles are actual poles.
It is proved that the sequence is completely uniformly distributed modulo 1 for almost all real numbers x with |x|> 1, if (an) is an arbitrary sequence of distinct positive integers.
Some interlacing properties of the zeros of the generalized Airy functions A1(z, p) are given for non-positive integral values of p. The result that A1 (z,p) has no real zero for is extended to show that all the zeros of A1(z,p) are real and simple if . It is also shown that all the zeros of the functions Bk(z,p, 1) for k = 1, 2, 3 are simple for non-positive integral p.