to perelman means to be working in complete isolation, without even your close friends or relatives knowing where you are and what you are up to
Example 1:
A: Haven't seen you in ages. Do you go to cafeteria for dinner at all?
B: No. In fact I am stressed because of exams, so I am perelmaning all day long, sleeping for 7 hours, and eating frozen food.
Example 2:
A: Oh by the way, how is C doing?
B: I have no idea, probably perelmaning in his room, again?..