Abstract. The purpose of this paper is to study the (strongly) Cesaro conull FKspaces and to give some characterizations.
IntroductionThe classification of conservative matrices as conull or coregular, due to Wilansky [14], has been extended by Yurimyae [17] and Snyder [13] to all FK-spaces. Bennett [2] continued work on conull FK-spaces; and improved some results of Sember [10]- [12].Motivating by Bennett's paper [2] and his talks at the Ankara University during the summer of 1996 we study the (strongly) Cesaro conull FK-spaces.In Section 2 we introduce the notation and terminology while in Section 3 we study the Cesaro conull FK-spaces and provide some examples to illustrate the differences between the conull and Cesaro conull FK-spaces. Section 4 deals with the strongly Cesaro conull FK-spaces; and gives a relationship between the (Cesaro wedge) weak Cesaro wedge and (strongly) Cesaro conull FK-spaces. In Section 5 we obtain some results for a summability domain EA to be (strongly) Cesaro conull. Section 6 presents some applications to summability domains.
Notation and preliminary resultsLet w denote the space of all real or complex-valued sequences. It can be topologized with the seminorms Pi(x) = |xi|, (i = 1,2,...), and any vector subspace of w is called a sequence space. A sequence space X, with a vector space topology T, is a K-space provided that the inclusion mapping By m,c, Co we denote the spaces of all bounded sequences, convergent sequences and null sequences, respectively. These are FK-spaces under ||a:|| = sup fc By £ p , (1 < p < oo), and cs we shall denote the space of all absolutely p-summable sequences, and convergent series, respectively. As usual i 1 is replaced by I. The sequence spaces The subspace of a locally convex sequence space X consisting of the sequences with the property AK (respectively oK) is denoted by XAK (respectively X a x). Every AK-space is a oK-space, [4]. For example Finally, s = {s n }^Li always denotes a strictly increasing sequence of non-negative integers with si = 0. We shall also be interested in spaces of the form SN+L c|s| := |a; G w : limij = 0 and sup ^ j|Aa;j|