A λ-rough set model and its applications with TOPSIS method to decision making

As an extension of classical rough sets, the concept of lambda-rough sets is introduced in information systems. We put forward the notions of lambda-indiscernibility relation and lambda-approximation space in information systems. The properties of roughness for lambda-approximation space are explored. To illustrate the usefulness of lambda-approximation spaces, we provide two approaches to deal with a special type of multiattribute decision making problems. By comparative analysis, the ranking results based on two different approaches have a high consensus. Although there are some different ranking results of these two methods, the optimal selected alternative is the same. (C) 2018 Elsevier B.V. All rights reserved.