On almost coincidence points in generalized convex spaces.
On (A,m)-expansive operators
We give several conditions for (A,m)-expansive operators to have the single-valued extension property. We also provide some spectral properties of such operators. Moreover, we prove that the A-covariance of any (A,2)-expansive operator T ∈ ℒ(ℋ ) is positive, showing that there exists a reducing subspace ℳ on which T is (A,2)-isometric. In addition, we verify that Weyl's theorem holds for an operator T ∈ ℒ(ℋ ) provided that T is (T*T,2)-expansive. We next study (A,m)-isometric operators as a special...
On an abstract evolution equation with a spectral operator of scalar type.
On an application of a Newton-like method to the approximation of implicit functions
On an elasto-dynamic evolution equation with non dead load and friction
In this paper, we are interested in the dynamic evolution of an elastic body, acted by resistance forces depending also on the displacements. We put the mechanical problem into an abstract functional framework, involving a second order nonlinear evolution equation with initial conditions. After specifying convenient hypotheses on the data, we prove an existence and uniqueness result. The proof is based on Faedo-Galerkin method.
On an estimate for the norm of a function of a quasihermitian operator
Let A be a closed linear operator acting in a separable Hilbert space. Denote by co(A) the closed convex hull of the spectrum of A. An estimate for the norm of f(A) is obtained under the following conditions: f is a holomorphic function in a neighbourhood of co(A), and for some integer p the operator is Hilbert-Schmidt. The estimate improves one by I. Gelfand and G. Shilov.
On an evolution equation in Banach spaces
On an exponential-cosine operator-valued functional equation.
On an Exponential-Cosine Operator-Valued Functional Equation. (Short Communication).
On an inclusion between operator ideals
Let and . We prove that , the ideal of operators of Geľfand type , is contained in the ideal of -absolutely summing operators. For this generalizes a result of G. Bennett given for operators on a Hilbert space.
On an inequality involving power and contraction of matrices with and without trace.
On an inequality of Kolmogorov type for a second-order difference expression.
On an infinite-dimensional version of the Kreiss matrix theorem
On an initial inverse problem in nonlinear heat equation associated with time-dependent coefficient
In this paper, a nonlinear backward heat problem with time-dependent coefficient in the unbounded domain is investigated. A modified regularization method is established to solve it. New error estimates for the regularized solution are given under some assumptions on the exact solution.
On an integral equation with modified argument.
On an integral of fractional power operators
For a bounded and sectorial linear operator V in a Banach space, with spectrum in the open unit disc, we study the operator . We show, for example, that Ṽ is sectorial, and asymptotically of type 0. If V has single-point spectrum 0, then Ṽ is of type 0 with a single-point spectrum, and the operator I-Ṽ satisfies the Ritt resolvent condition. These results generalize an example of Lyubich, who studied the case where V is a classical Volterra operator.
On an integral operator in the space of functions with bounded variation. II.
On an integral operator in the space of functions with bounded variation
On an integral operator on the unit ball in .
On an integral representation of antisymmetric operations in Hilbert spaces. I. Bounded operations