Affiliations: Institute of Mathematics, University of Warsaw,
Banacha 2, 02-097 Warszawa, Poland | Department of Computer Science, Białystok University of Technology, Wiejska 45A, 15-351 Białystok, Poland | Department of Electrical and Computer Engineering, University of Manitoba, Winnipeg, Manitoba R3T 5V6, Canada
Abstract: We discuss the relationships between information systems and
classifications as well as between infomorphisms and definability of relations
(between whole objects and their parts) in information systems. Infomorphisms
between information systems (classifications) IS_1 and IS_2 make it
possible to define some formulas over IS_2 by means of formulas over IS_1.
The remaining formulas over IS_2 can be approximatively defined by means of
formulas over IS_1. The approximation operations are defined using the rough
set approach. We present definitions and examples of such approximations.
Keywords: information systems, classifications, rough set theory, infomorphisms, definability, approximations, approximate reasoning, information nets
