Gleb Koshevoy (Russian Academy of Siences), Feb-March, 2017.
Shmuel Friedland (University of Illinois at Chicago), one week in May 2017.
Zheng Qu (Hong Kong University), June-July 2017
Zheng Hua (Hong Kong University), June-July 2017
Rajendra Bhatia (Indian Statistical Institute, New Delhi), 1 week in Dec 2017.
Floris Claassens (University of Kent), 1 week in Dec 2017.