A Survey on Spherical Fuzzy Sets and Clustering the Literature

Abstract

In addition to the well-known fuzzy sets, a novel type of fuzzy sets called as spherical fuzzy set (SFS) is recently introduced in the literature. SFS is the generalized structure over existing structures of fuzzy sets (intuitionistic fuzzy sets, Pythagorean fuzzy sets, and neutrosophic sets) based on three dimensions (truth, falsehood, and indeterminacy) to provide a wider choice for decision makers (DMs). Although the SFS is introduced recently, the topic attracts the attention of academicians at a remarkable rate. Hence, a comprehensive literature review of recent and state-of-the-art papers is vital to draw a framework of the past, and to shed light on future directions. To do so, a systematic review methodology is followed and 43 academic papers include SFS are selected and reviewed. The papers are then analyzed and categorized based on the titles and abstracts to construct a useful foundation of past research. Finally, trends and gaps in the literature are identified to clarify and to suggest future research opportunities in fuzzy logic area. © 2021, The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG.