If I remember it correctly, a Prof at Peking U also refused 摘帽右派与改正右派 about him/her.
This person became a 右派 in 1950s. In 1980s, he was asked to participate a meeting about taking off the hat. He/she refused to go the meeting, and replied: the hat was put on my head by you, and now it is you to take it off. It has nothing to do with me.
I am quite confident that the person is not from math dept. Otherwise, I should know.
If he or she is from physics dept, Borisq could know.