The authors proved in [6] that the implication (*) MOWECF => MnWECWr holds for every separable FK-space F, for every FK-space E containing the set (p of all finite (real er complex valued) sequences, and for each sequence space M having suitable factor sequences; thereby We denotes the set of all elements of E being weakly sectionally convergent. This result was proved by the first author [4] under the additional assumption that M is an FK-AB-space and by both authors [5] under the same assumption and in the special case that is a summability domain. For the "history" of such theorems of Mazur-Orlicz type we refer for example to [6]. On the base of the examinations of distinguished subspaces of FK-spaces over an F-space X (FK(X)-spaces) in [7] (see also [2] and [10]) we prove in section 2 of the present paper that the implication (*) remains true if, in addition, E is an FK(X)-space eind F is a summability domain of a suitable operator valued matrix. Proving an inclusion theorem we show in section 3 that a light variant of implication (») remains true in case of weak domains of operator valued matrices. In section 4 we get -quite similar to the classical case -as immediate corollaries of the Theorems of Mazur-Orlicz-type some consistency theorems containing, for example, operator bounded consistency theorems due to A. Alexiewicz and W. Orlicz (see [1] and [9, Theorem 6.27]). We complete the paper with an example of operator valued matrices related to almost convergence which proves that it is of mathematical interest to consider weak domains of operator valued matrices. AMS 1980 Classification: 40J05, 40H05, 40C99, 40D99, 46A45
Notations and preliminariesFor basic definitions, notations and preliminaries, especially for the notion of FK(X)-spaces, we refer to [7]. Throughout the whole paper we assume that (X,TX) and {Y,TY) are (locally convex) Frechet spaces (F-spaces) and, as usually, B{X, Y) denotes the set of all continuous linear maps from X ' to y. Furthermore we assume that Z is a linear subspace of V such that (V, Z) is a total dual pair. Apart from the sequence spaces , m(X) , c(A'), co(X), ip(X) and 1{X') defined in [7] we consider in the current paper the following sequence spaces (over X):Brought to you by | University of Pennsylvania Authenticated Download Date | 6/14/15 7:46 PM