A bounded consistency theorem for strong summabilities.
A complex Tauberian theorem and mean ergodic semigroups.
A new class of sequence spaces with applications in summability theory.
A new proof of multisummability of formal solutions of non linear meromorphic differential equations
We give a new proof of multisummability of formal power series solutions of a non linear meromorphic differential equation. We use the recent Malgrange-Ramis definition of multisummability. The first proof of the main result is due to B. Braaksma. Our method of proof is very different: Braaksma used Écalle definition of multisummability and Laplace transform. Starting from a preliminary normal form of the differential equationthe idea of our proof is to interpret a formal power series solution...
A note on Köthe-Toeplitz duals of certain sequence spaces and their matrix transformations.
A summability integral.
Absolute and Ordinary Köthe-Toeplitz Duals of Some Sets of Sequences and Matrix Transformations
Addendum to: "Sequences of 0's and 1's" (Studia Math. 149 (2002), 75-99)
There is a nontrivial gap in the proof of Theorem 5.2 of [2] which is one of the main results of that paper and has been applied three times (cf. [2, Theorem 5.3, (G) in Section 6, Theorem 6.4]). Till now neither the gap has been closed nor a counterexample found. The aim of this paper is to give, by means of some general results, a better understanding of the gap. The proofs that the applications hold will be given elsewhere.
An example of nonlinear -difference equation
An extension of Brudno-Mazur-Orlicz theorem
An Extension of Cauchy's Criterion to Nörlund Summability.
An IntroduCtion into the Theory of Sequence Spaces and Measures of Noncompactness
Asymptotic properties of convolution products of sequences.