A generalized model of three-way decision with ranking and reference tuple

The theory of three-way decision was originally introduced as three regions to explain rough sets. Nowadays we can apply this theory to many important fields by defining reasonable trisecting rules. In this paper, we reconsider the two-universe model of three-way decision proposed by Xu et al. and extend it to a more general level. Specifically, we introduce a pair of thresholds to the model and propose a generalized model of three-way decision with ranking and reference tuple. We prove that, although the pairs of thresholds are infinite, we only need to consider a finite number of pairs of thresholds and their corresponding trisections. Based on this theoretical foundation, we further define a unique measure to assess the trisections, compare trisections through this measure, and propose an algorithm to compute the optimal trisection in finite steps. By comparison with other models and an example of application, we demonstrate that the generalized model is more expressive and more practical than the previous one, and has some advantages over the compared models in accuracy of trisecting and validity of explaining. (C)& nbsp;2022 Elsevier Inc. All rights reserved.

Automated summary

This paper reconsiders the binary model of three-way decision and extends it to a more general case. By introducing a pair of thresholds and defining a corresponding measure, an algorithm to compute the optimal trisection is proposed. Comparisons with other models and application examples demonstrate the superiority of the generalized model.