**7. Conclusions**

In this paper, we propose two complex fuzzy aggregation operators: the CFWG and CFOWG operators. Their main properties are summarized in Table 1. In particular, both the CFWG and the CFOWG operators are reflectionally invariant and rotationally invariant. We also showed that the CFWG and the CFOWG operators are closed under Π − *i* numbers.

As we know, complex data are frequently encountered in many different applications, such as engineering, management, finance, and medicine. CFSs are suitable to represent information with uncertainty and periodicity simultaneously. Complex fuzzy information aggregation techniques may be useful in these applications.

**Author Contributions:** Conceptualization, S.D.; Project administration, L.B. and B.H.; Writing-original draft, L.B., S.D. and B.H.; Writing-review and editing, L.B., S.D. and B.H.

**Acknowledgments:** The authors would like to thank the anonymous referees and academic editor for their very valuable comments.

**Funding:** This research was funded by the Opening Foundation of Guangxi Colleges and Universities Key Laboratory of Complex System Optimization and Big Data Processing (Grant No. 2017CSOBDP0103), the Science and Technology Foundation of Guizhou Province, China (LKS [2013] 35 and LKS (2012) 34), and the Guangxi University Science and Technology Research Project (Grant No. 2013YB193).

**Conflicts of Interest:** The author declares no conflict of interest.
