On November 26, 2020, Yexing Dan successfully defended his Ph.D. thesis "On the construction of four types of associative aggregation operators on bounded lattices" at Wuhan University, China. He was awarded the title of Doctor of Computational Mathematics. He was jointly supervised by Bao Qing Hu and Bernard De Baets. Yexing spent one year at KERMIT supported by the China Scholarship Council. The defense took place in Wuhan, the epicenter of the pandemic, live and without face masks!