, and then mathematicians wanted to compete and be have their own version of kevin bacon which is the man who collaborated with many, many mathematicians, so the question is how far are you away from having written a paper with air attorney? people said let's put it all together and see how far an individual is from kevin bacon and the mathematician. as you can imagine, there aren't too many people, but there are a handful of us, and i'm one of them. >> how many are you? >> i used to be the world leader. >> what's your number? >> number five. i've been overtaken. >> five in what? >> five total. two from the mathematician and three from bacon, or something like that. [laughter] but i think, like, gwyneth paltrow has taken -- she wrote a paper. yeah, i'm not sure. there are definitely people who have taken over. >> i see. in another universe, you're number one. >> that's always going to be the case, yes. >> so what is this -- let me ask you, we all think that there's one universe. how could there be more? >> yeah. well, that is the essential question to start with. because, you know