MO is currently being the focus of what I guess to be a single particular individual R.T.Man sporting multiple unregistered users identity (like Eskand or H.night). S/he's asking multiple very similar and basic questions in the topic of «matrix polynomial» and other related topological issues (like this one but other very similar questions seem to appear and disappear shortly afterwards on a regular basis). I'm fed up voting to close and seeing again and again the same questions popping up. I'm sure moderators noticed that little game, as Todd closed single-handedly at least one post (here).
Can something be done in terms of IP filtering or is the user abusing the system by vpn-ing his/her entry here?
More generally, what can the community do about such behavior? What should be the right route to convince him/her of stopping being such a pain in the good-will of others?