240 research outputs found
The inhomogeneous Cauchy-Riemann equation for weighted smooth vector-valued functions on strips with holes
This paper is dedicated to the question of surjectivity of the Cauchy-Riemann
operator on spaces of -smooth
vector-valued functions whose growth on strips along the real axis with holes
is induced by a family of continuous weights . Vector-valued
means that these functions have values in a locally convex Hausdorff space
over . We characterise the weights which give a
counterpart of the Grothendieck-K\"othe-Silva duality
with non-empty compact for weighted holomorphic functions.
We use this duality to prove that the kernel
of the Cauchy-Riemann operator
in
has the property
of Vogt. Then an application of the splitting theory of Vogt for
Fr\'{e}chet spaces and of Bonet and Doma\'nski for (PLS)-spaces in combination
with some previous results on the surjectivity of the Cauchy-Riemann operator
yields
the surjectivity of the Cauchy-Riemann operator on if
with some Fr\'{e}chet space satisfying the condition or
if is an ultrabornological (PLS)-space having the property . This
solves the smooth (holomorphic, distributional) parameter dependence problem
for the Cauchy-Riemann operator on
Surjectivity of the -operator between spaces of weighted smooth vector-valued functions
We derive sufficient conditions for the surjectivity of the Cauchy-Riemann
operator between spaces of weighted smooth
Fr\'echet-valued functions. This is done by establishing an analog of
H\"ormander's theorem on the solvability of the inhomogeneous Cauchy-Riemann
equation in a space of smooth -valued functions whose topologyis
given by a whole family of weights. Our proof relies on a weakened variant of
weak reducibility of the corresponding subspace of holomorphic functions in
combination with the Mittag-Leffler procedure. Using tensor products, we deduce
the corresponding result on the solvability of the inhomogeneous Cauchy-Riemann
equation for Fr\'echet-valued functions
Extension of vector-valued functions and sequence space representation
We give a unified approach to handle the problem of extending functions with
values in a locally convex Hausdorff space over a field , which
have weak extensions in a space of
scalar-valued functions on a set , to functions in a vector-valued
counterpart of . The
results obtained base upon a representation of vector-valued functions as
linear continuous operators and extend results of Bonet, Frerick, Gramsch and
Jord\'{a}. In particular, we apply them to obtain a sequence space
representation of from a known representation of
.Comment: The former version arXiv:1808.05182v2 of this paper is split into two
parts. This is the first par
Weighted Composition Semigroups on Spaces of Continuous Functions and Their Subspaces
This paper is dedicated to weighted composition semigroups on spaces of continuous functions and their subspaces. We consider semigroups induced by semiflows and semicocycles on Banach spaces F(Ω) of continuous functions on a Hausdorff space Ω such that the norm-topology is stronger than the compact-open topology like the Hardy spaces, the weighted Bergman spaces, the Dirichlet space, the Bloch type spaces, the space of bounded Dirichlet series and weighted spaces of continuous or holomorphic functions. It was shown by Gallardo-Gutiérrez, Siskakis and Yakubovich that there are no non-trivial norm-strongly continuous weighted composition semigroups on Banach spaces F(D) of holomorphic functions on the open unit disc D such that H∞⊂F(D)⊂B1 where H∞ is the Hardy space of bounded holomorphic functions on D and B1 the Bloch space. However, we show that there are non-trivial weighted composition semigroups on such spaces which are strongly continuous w.r.t. the mixed topology between the norm-topology and the compact-open topology. We study such weighted composition semigroups in the general setting of Banach spaces of continuous functions and derive necessary and sufficient conditions on the spaces involved, the semiflows and semicocycles for strong continuity w.r.t. the mixed topology and as a byproduct for norm-strong continuity as well. Moreover, we give several characterisations of their generator and their space of norm-strong continuity.</p
The abstract Cauchy problem in locally convex spaces
We derive sufficient criteria for the uniqueness and existence of solutions
of the abstract Cauchy problem in locally convex Hausdorff spaces. Our approach
is based on a suitable notion of an asymptotic Laplace transform and extends
results of Langenbruch beyond the class of Fr\'echet spaces
Mixed topologies on Saks spaces of vector-valued functions
We study Saks spaces of functions with values in a normed space and the associated mixed topologies. We are interested in properties of such Saks spaces and mixed topologies which are relevant for applications in the theory of bi-continuous semigroups. In particular, we are interested if such Saks spaces are complete, semi-Montel, C-sequential or a (strong) Mackey space with respect to the mixed topology. Further, we consider the question whether the mixed and the submixed topology coincide on such Saks spaces and seek for explicit systems of seminorms that generate the mixed topology.</p
On linearisation and existence of preduals
We study the problem of existence of preduals of locally convex Hausdorff spaces. We derive necessary and sufficient conditions for the existence of a predual with certain properties of a bornological locally convex Hausdorff space X. Then we turn to the case that X=F(Ω) is a space of scalar-valued functions on a non-empty set Ω and characterise those among them which admit a special predual, namely a strong linearisation, i.e. there are a locally convex Hausdorff space Y, a map δ:Ω→Y and a topological isomorphism T:F(Ω)→Yb′ such that T(f)∘δ=f for all f∈F(Ω).</p
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