Neste trabalho estudamos a integral de Kurzweil para funções definidas em um intervalo fechado limitado da reta e a valores em um espaço de Riesz. Apresentamos algumas propriedades básicas dessa integral e teoremas que relacionam a convergência uniforme de uma seqüência de funções Kurzweil integráveis com a convergência da seqüência formada pelas respectivas integrais. / In this work we study the Kurzweil integral for functions defined in a compact interval and with values in a Riesz space. We present some elementary properties for this integral and we prove theorems that relate the uniform convergence of a sequence of Kurzweil integrable functions to the convergence of the sequence of their integrals.

Neste trabalho estudamos a integral de Kurzweil para funções definidas em um intervalo fechado limitado da reta e a valores em um espaço de Riesz. Apresentamos algumas propriedades básicas dessa integral e teoremas que relacionam a convergência uniforme de uma seqüência de funções Kurzweil integráveis com a convergência da seqüência formada pelas respectivas integrais. / In this work we study the Kurzweil integral for functions defined in a compact interval and with values in a Riesz space. We present some elementary properties for this integral and we prove theorems that relate the uniform convergence of a sequence of Kurzweil integrable functions to the convergence of the sequence of their integrals.

The present work consists of two main parts. In the first part, invariant subspaces of positive operators or operator families on locally convex solid Riesz spaces are examined. The concept of a weakly-quasinilpotent operator on a locally convex solid Riesz space has been introduced and several results that are known for a single operator on Banach lattices have been generalized to families of positive or close-to-them operators on these spaces. In the second part, the so-called generalized Alexandroff duplicates are studied and CDsigma, gamma(K, E)-type spaces are investigated. It has then been shown that the space CDsigma, gamma(K, E) can be represented as the space of E-valued continuous functions on the generalized Alexandroff duplicate of K.

In this thesis, we study two problems. The first problem is to introduce the general version of Abramovich-Wickstead type spaces and investigate its order properties. In particular, we study the ideals, order bounded sets, disjointness properties, Dedekind completion and the norm properties of this Riesz space. We also define a new concrete example of Riesz space-valued uniformly continuous functions, denoted by CDr0 which generalizes the original Abramovich-Wickstead space. It is also shown that similar spaces CD0 and CDw introduced earlier by Alpay and Ercan are decomposable lattice-normed spaces. The second problem is related to analytic representations of different classes of dominated operators on these spaces. Our main representation theorems say that regular linear operators on CDr0 or linear dominated operators on CD0 may be represented as the sum of integration with respect to operator-valued measure and summation operation. In the case when the operator is order continuous or bo-continuous, then these representations reduce to discrete parts.