Das Lomonosov-Lemma für topologische Vektorräume.
Das Spektrum von Verbandsoperatoren in Banachverbänden.
Das verallgemeinerte Inverse eines linearen Operators in Vektorräumen mit nicht ausgearteter Hermitescher Metrik über einenm kommutativen Körper.
Decomposable embeddings, complete trajectories, and invariant subspaces
We produce closed nontrivial invariant subspaces for closed (possibly unbounded) linear operators, A, on a Banach space, that may be embedded between decomposable operators on spaces with weaker and stronger topologies. We show that this can be done under many conditions on orbits, including when both A and A* have nontrivial non-quasi-analytic complete trajectories, and when both A and A* generate bounded semigroups that are not stable.
Decomposable subspaces of Banach spaces.
We introduce and study the notion of hereditarily A-indecomposable Banach space for A a space ideal. For a hereditarily A-indecomposable space X we show that the operators from X into a Banach space Y can be written as the union of two sets A Φ+(X,Y) and A(X;Y ). For some ideals A defined in terms of incomparability, the first set is open, the second set correspond to a closed operator ideal and the union is disjoint.
Decomposable systems of differential operators and generalized inverses
Décomposition et classification des systèmes dynamiques
Decomposition of homogeneous vector fields of degree one and representation of the flow
Decomposition of operators with countable spectrum.
Sufficient spectral conditions for the existence of a spectral decomposition of an operator T defined on a Banach space X, with countable spectrum, are given. We apply the results to obtain the West decomposition of certain Riesz operators.
Decompositions and asymptotic limit for bicontractions
The asymptotic limit of a bicontraction T (that is, a pair of commuting contractions) on a Hilbert space is used to describe a Nagy-Foiaş-Langer type decomposition of T. This decomposition is refined in the case when the asymptotic limit of T is an orthogonal projection. The case of a bicontraction T consisting of hyponormal (even quasinormal) contractions is also considered, where we have .
Decompositions for real Banach spaces with small spaces of operators
We consider real Banach spaces X for which the quotient algebra (X)/ℐn(X) is finite-dimensional, where ℐn(X) stands for the ideal of inessential operators on X. We show that these spaces admit a decomposition as a finite direct sum of indecomposable subspaces for which is isomorphic as a real algebra to either the real numbers ℝ, the complex numbers ℂ, or the quaternion numbers ℍ. Moreover, the set of subspaces can be divided into subsets in such a way that if and are in different subsets,...
Decompositions of tensor products of contractions
Definition Theory and Systems of Simultaneous Equations in the Perdual of an Operator Algebra. II.
Degeneration and complexity of bilinear maps: Some asymptotic spectra.
Dense range perturbations of hypercyclic operators
We show that if (Tₙ) is a hypercyclic sequence of linear operators on a locally convex space and (Sₙ) is a sequence of linear operators such that the image of each orbit under every linear functional is non-dense then the sequence (Tₙ + Sₙ) has dense range. Furthermore, it is proved that if T,S are commuting linear operators in such a way that T is hypercyclic and all orbits under S satisfy the above non-denseness property then T - S has dense range. Corresponding statements for operators and sequences...
Dense sets and far-field patterns for the vector thermoelastic equation
Denting point in the space of operator-valued continuous maps.
In a former paper we describe the geometric properties of the space of continuous functions with values in the space of operators acting on a Hilbert space. In particular we show that dent B(L(H)) = ext B(L(H)) if dim H < 8 and card K < 8 and dent B(L(H)) = 0 if dim H < 8 or card K = 8, and x-ext C(K,L(H)) = ext C(K,L(H)).
Dependence of fractional powers of elliptic operators on boundary conditions
The realization of an elliptic operator A under suitable boundary conditions is considered and the dependence of the square-root of A from the various conditions is studied.
Dependence of the buckling load of a nonshallow arch with respect to the shape of its midcurve
Der spektrale Abbildungssatz für nichtanalytische Funktionalkalküle in mehreren Veränderlichen.