Class-specific information measures and attribute reducts for hierarchy and systematicness

•Class-specific information measures are constructed by hierarchical decomposition.•Two-level systems of information measures exhibit a hierarchical isomorphism.•Informational class-specific reducts are proposed for class recognition optimization.•Informational class-specific reducts gain criss-cross connections with old modes.•Two-level and two-view reduct systems contain vertical and horizontal isomorphisms.