Hemen hemen ayrışan grupların parçalanması

Almost completely decomposable groups are extensions of completely decomposable groups of finite index. They can be written as a sum of indecomposables. Every almost completely decomposable group is the direct sum of indecomposables but this decomposition is quite complicated and not unique. Almost completely decomposable groups can be represented by matrices, called coordinate matrices. If the coordinate matrix of a given almost completely decomposable group is decomposable then the group is decomposable. Under some restrictions, for example considering a weakening of isomorphism, called near-isomorphism some spacial classes of almost completely decomposable groups can be classified.