I'm quite puzzled as well. As far as I can tell (not a lawyer) copyright law shouldn't apply at all in this case. According to the article the actual works perf

I'm quite puzzled as well. As far as I can tell (not a lawyer) copyright law shouldn't apply at all in this case. According to the article the actual works performed were an excerpt from Hamlet (public domain) and a song by Billy Joel (so someone likely has a valid copyright claim, but probably not Jay-Z). On the other hand, it seems like it might well be an infringement of his likeness (ie a trademark violation). I'm not sure about the nuances surrounding trademark law though - does it have to make money, do intentions matter, how obvious does it need to be that this is an impersonation, etc.