Best order conditions in linear spaces, with applications to limitation, inclusion and high indices theorems for ordinary and absolute Riesz means
We study in terms of corresponding Köthe matrices when every continuous linear operator between two Köthe spaces is bounded, the consequences of the existence of unbounded continuous linear operators, and related topics.
Characterizations of pairs (E,F) of complete (LF)?spaces such that every continuous linear map from E to F maps a 0?neighbourhood of E into a bounded subset of F are given. The case of sequence (LF)?spaces is also considered. These results are similar to the ones due to D. Vogt in the case E and F are Fréchet spaces. The research continues work of J. Bonet, A. Galbis, S. Önal, T. Terzioglu and D. Vogt.
In this paper we generalize some results concerning bounded variation functions on sequence spaces.
In this paper we define new sequence spaces using the concepts of strong summability and boundedness of index of -th order difference sequences. We establish sufficient conditions for these spaces to reduce to certain spaces of null and bounded sequences.
In this paper we deal with Cesàro wedge and weak Cesàro wedge -spaces, and give several characterizations. Some applications of these spaces to general summability domains are also studied.
We characterize Köthe echelon spaces (and, more generally, those Fréchet spaces with an unconditional basis) which are Schwartz, in terms of the convergence of the Cesàro means of power bounded operators defined on them. This complements similar known characterizations of reflexive and of Fréchet-Montel spaces with a basis. Every strongly convergent sequence of continuous linear operators on a Fréchet-Schwartz space does so in a special way. We single out this type of "rapid convergence" for a sequence...