Key wmls: Generalized contractions, fixed point theorems. convergence of sequence of iterates. 1. INTRODUCTION THE STUDY in fixed point theory has generally developed in three main directions: generalization of conditions which ensure existence, and, if possible, uniqueness, of fixed points; investigation of the character of the sequence of iterates (T "… (More)
In this paper we present a new Multiple Sequence Alignment (MSA) algorithm called AntiClusAl. The method makes use of the commonly use idea of aligning homologous sequences belonging to classes generated by some clustering algorithm, and then continue the alignment process ina bottom-up way along a suitable tree structure. The final result is then read at… (More)
We show that as soon as c 0 embeds complementably into the space of all weakly compact operators from X to Y , then it must live either in X * or in Y. the space of all compact operators from X to Y equipped with the operator norm, even if it does not embed into X * and Y ; furthermore, such a copy of c 0 can be complemented in K(X, Y) (see [E4], [E6]).… (More)
In this short note we want to present two remarks improving two results contained in the papers [C] and [O], the first one about the Dunford–Pettis property and the second one about the containment of complemented copies of l 1 in certain tensor products of Banach spaces. Before starting we remark that our notations are taken from the book [DF]. The first… (More)
We show results about the existence and the nonexistence of a projection from the space L(L 1 (λ), X) of all linear and bounded operators from L 1 (λ) into X onto the subspace R(L 1 (λ), X) of all representable operators.
Using some known lifting theorems we present three-space property type and permanence results; some of them seem to be new, whereas other are improvements of known facts. This short note is devoted to the proof of certain results showing that some isomorphic properties of Banach spaces or of operators between Banach spaces have some nice permanence… (More)