In my opinion, people who say that kind of stuff usually don't know what they're talking about. As far as I know, the only particularly mathematical thing that Meshuggah do is use odd time signatures and polyrythms. From a mathematical point of view, it's no more advanced than fractions. I HIGHLY doubt that Meshuggah use math for anything else, and I think you'll find that the more one conciously uses advanced math to compose music, the less listenable it is. You can find complex patterns in a lot of music if you go looking for it, but that doesn't mean that composers sit down an solve equations to make it. There is also a relationship between trigonometry and music, but it's mainly interesting from an analytic point of view, and isn't really something most people think of when making it. I could go into more detail, but I think I've proably said too much already!