*Article* **Complex Fuzzy Geometric Aggregation Operators**

**Lvqing Bi 1, Songsong Dai 2,\* and Bo Hu 2,3**


Received: 15 June 2018; Accepted: 28 June 2018; Published: 2 July 2018

**Abstract:** A complex fuzzy set is an extension of the traditional fuzzy set, where traditional [0,1]-valued membership grade is extended to the complex unit disk. The aggregation operator plays an important role in many fields, and this paper presents several complex fuzzy geometric aggregation operators. We show that these operators possess the properties of rotational invariance and reflectional invariance. These operators are also closed on the upper-right quadrant of the complex unit disk. Based on the relationship between Pythagorean membership grades and complex numbers, these operators can be applied to the Pythagorean fuzzy environment.

**Keywords:** complex fuzzy sets; aggregation operator; complex fuzzy geometric operators; rotational invariance; reflectional invariance
