Seminars and Talks 10:15 - 11:15, September 11, 2020 (Friday) Zoom, Online seminar Counting Sheaves on Calabi-Yau 4-folds 9:00 - 10:00, September 11, 2020 (Friday) Zoom, Online seminar Birationality Centers and Cremona Groups Conferences, Workshops and Special Events September 7 - 11, 2020 Japan-Taiwan Joint conference on Number theory 2020 (Postpone:2021/09/13-09/17) September 9 - 11, 2020 The Taiwan Number Theory Symposium