  Motivated by the application problem of sensor fusion the author introduced
the concept of graded set. It is reasoned that in classification problem
arising in an information system (represented by information table), a novel
set called Granular set naturally arises. It is realized that in any
hierarchical classification problem, Granular set naturally arises. Also when
the target set of objects forms a graded set the lower and upper approximations
of target sets form a graded set. This generalizes the concept of rough set. It
is hoped that a detailed theory of granular/ graded sets finds several
applications.
