Approximation of Classification and Measures of Uncertainty in Rough Set
  on Two Universal Sets
  The notion of rough set captures indiscernibility of elements in a set. But,
in many real life situations, an information system establishes the relation
between different universes. This gave the extension of rough set on single
universal set to rough set on two universal sets. In this paper, we introduce
approximation of classifications and measures of uncertainty basing upon rough
set on two universal sets employing the knowledge due to binary relations.
