OICC Press Mathematical Analysis and its Contemporary Applications 5 1 2023 01 01 T-norms over complex fuzzy subgroups 10.30495/maca.2022.1964436.1061 EN Rasul Rasuli Department of Mathematics, Payame Noor University, P. O. Box 19395-3697, Tehran, Iran Journal Article 2023 01 01 In this paper, by using t-norms, we define complex fuzzy subgroups and normal complex fuzzy subgroups and investigate some of characteristics of them. Later we introduce and study the intersection and composition of them. Next, we define the concept of normality between two complex fuzzy subgroups under t-norms and obtain some properties of them. Finally, we define the image and the inverse image of them under group homomorphisms.