Bouziane, FairouzYahi, Rachid: Supervisor2024-07-032024-07-032024-06https://dspace.univ-msila.dz/handle/123456789/43139In this memory, we deal with one of the most important topics in functional analysis, namely some classes of compact sets and operators, we endeavored, with modest effort, to identify the most important definitions, theorems, and properties throughout all chapters of this research. In the first chapter, we review the key concepts related to compact sets and compact operators. The second chapter deals with some results related to relatively Kp,q-compact sets and finally we present some results for Kp,q-null sequence.encompact groupscompact Kpq groupsK-pa sequences that converge towards zeroeffectsK-pq compactnessapproximation propertyThesis