𝝂 −conull and 𝝂 −wedge fdk spaces

In this thesis, considering the concept of 𝝂−convergence for double sequences, (strong) 𝝂− conull and (weak) 𝝂−wedge FDK spaces for 𝝂∈{p,bp,r,c} are defined. On the other hand, the results of Bennett (1974) are analysed for (strong) 𝝂−conull and (weak) 𝝂−wedge FDK spaces. Moreover, the relation between the topological structure of such spaces and the compactness of inclusion maps is established. On the other hand, various characterizations of these spaces were obtained. Finally,some important applications of (strong) 𝝂−conull and (weak) 𝝂−wedge FDK spaces in the field of summability are given.